Sure, but the amount of difficulty seems so over the top.
Have you considered that you are artificially inflating the difficulty, by choosing not to use a build that the framework of secrets in the module caters toward?
Not to go back over the same ground as we've covered several times in the past, but the bottom line is that the game primarily offers rogues the means to "easily" discover/farm secrets. There are alternative avenues of approach, but these generally require one, two, or all three items of the following list: advanced knowledge, advanced gear, extra time/effort. You are not playing a "real" rogue, and you are making things much more difficult for yourself by exploring in a way that the module expects a real rogue to. You also are most likely not taking advantage of the alternative mechanisms that exist to make this job either easier for rogues, or easier for non-rogues. This is probably due to a combination of not knowing what these mechanisms are/how to get them, or not having an advanced enough "account" (in terms of gear/tags/loot hoard/etc) to attain them.
That just seems like overkill. If we at least got a level cap notice, we would know to come back at a lower level and stick our noses everywhere with search maxed.
I understand the frustration and I do sympathize with the feeling that it's "overkill," in the sense that you have to jump through too many hoops and bend over backwards to enjoy the rewards. Again, though, it may have occurred to you that you are not doing yourself any favors by using an unorthodox character to jump through hoops that are designed to be a bit easier for someone with a combination of "being a high-level rogue; having advanced knowledge of the game; having advanced items" to jump through. Unfortunately for you, the game is much quieter now than in the past, and this probably means that you're at a disadvantage compared to past players in your position, both due to fewer people online to answer !newbie channel questions, and fewer people to play with and interact with organically and learn from. On the one hand, I do think you are making things a bit harder than they should be by kind of "doing your own thing" and then hoping to get the answers or tips from public chats/forums when you hit a dead end, but on the other hand if this was years ago, you would likely have a much easier time of finding people doing similar activities to hang out with.
In the case of 1-40/PoA secrets, there has always been a general feeling of dissatisfaction from many players. The level caps are often so low that they seem nonsensical when taken in full context of the HG PoA mod and from the mindset/custom of an HG player. After lowbie tags become second nature and associating the lowbie acc level caps with different zones/maps, and associating given mobs with certain level ranges (which may or may not make much sense in the first place, due to PoA having such a long lifetime and so many changes on HG), the 1-40 secrets rarely--if ever--seem to allow organic playthrough discovery.
This, combined with the vastly-outdated, strange, or useless nature of the rewards, has lent the overall 1-40 secret structure a clear sense of being broken. (As well, to make matters worse, there are many things that were once built into PoA that have been changed or simply no longer exist in HG, meaning some things are simply broken and either only partially functional or nonfunctional--but that's besides the point of the proper "secrets" that do work but simply feel like a waste of time).
As for LL secrets, I think there has similarly been some degree of disgruntlement over the years, but this is often not so much about level caps being too low, or the overall scheme being too difficult and time-consuming in a way that feels like overkill; rather, there's some annoyance and frustration with accessing the secrets in some maps that are just a pain in the ass. There's some of the former, to be sure--for example, just like lowbie dragon gold piles "feel" like the level cap is far too low, probably every noob has at one point tried to click on DB's gold pile and been surprised and annoyed that they're too high level.
In the case of lowbie dragons, this feels surprising and frustrating because the lowbie tag cap is much higher than the gold pile cap, and players without proper knowledge/technique/party/gear may feel that the level they beat the dragon at is suitable, whereas going much lower level would be too risky or difficult--despite the fact that these dragons are, for the most part, doable at a far lower level, quite easily, and at a level at which the gold pile is attainable. Similarly, for Dustbone, completing the boss fight successfully is doable at a much lower level than commonly practiced, but the question of whether or not the gold pile is properly tagged is a matter of debate.
There are definitely some problems with the way that secrets are designed, and there are definitely some problems with the system as a whole. I think most players would agree to that. I don't think that the mysterious nature of the level caps or figuring out how to find them is really one of the primary complaints, because (as boroie mentioned) there are multiple devices for finding secrets with locate object, and combined with "passed-down" or shared knowledge, secret locations/level caps tend to be the easier half of the puzzle, when compared to spending the time and effort actually collecting them once you know where to look.
As you mentioned, the random nature of which spots are active means that even bringing a character/party of the proper level (often requiring shackling or a lower-level toon, for some LL runs--just like PoA secrets) still requires repeating the run multiple times, just as if you are farming for %-based loot. This grind is generally distasteful for most players, but whether it's a matter of annoyance that brings pride to spend the time and effort to collect the rewards, or whether it's just a poor system that is too punishing--that's a matter of debate, as well.
The one thing that most players who "don't mind the grind" for secrets (and players who do successfully devote time and effort to farming them) to tend to agree on is the fact that some maps, and some runs, have secrets that are just really obnoxious and aggravating to farm. Sometimes, this is because there are secrets in annoying spots, sometimes it's because some maps are just a pain in the ass, sometimes the secrets are "not worth" collecting, sometimes the entire run is filled with one or both of those features, and sometimes it's because the run is such a time/effort investment that, when combined with any or all of the above, the prospect of doing the run to farm the secrets is just too painful to bother with. Some of these runs are even considered to be either not worth searching on even when the run is done for other reasons, not worth running for secrets alone, or most "secret-savvy" vets will pick and choose which maps/secrets to bother checking.
I think that the system is overall pretty well-tailored to be rewarding enough that those with the time, knowledge, gear, and mindset are willing to jump through hoops to collect secrets, while at the same time being punishing enough that players that don't have the patience, time, knowledge, or ability to collect secrets are prevented from doing so (and these players may then have a role in the economy by trading with secret-collectors if/when they need secrets). In all, it feels about right to me. There's definitely some flaws, but taken as a whole I really think the system is pretty good. It manages to keep enough of a "secret" nature that you feel accomplished once you figure out (or get told/read others' lore) The Things, and it's manageable enough for vet secret-farmers to grab secrets and have it be worth their time and effort. It's difficult enough that it's challenging and unappealing to figure out The Things on your own (especially without using a rogue and rogues' gear), which is proper, in my opinion; at the same time, it's not so difficult that no one bothers.
I think the problems with some secrets/runs/maps feeling too punishing could and should be fixed, in a perfect world, but that seems extremely unlikely to ever be done. As for being too difficult, or overkill, I think that in time and with a different perspective, you may come to appreciate the system more, or at any rate, not feel that it is quite as difficult or punitive as you do now. It's too bad that, as with any game, secret lore becomes more and more punishing for newer/inexperienced players as time passes and population drops and lore resources become less and less available, but whether that's part of the charm or something that needs to be coded to adjust for shifted expectations is probably a debate that isn't worth having, since it's unlikely for anything to change at this point, anyway.