Modern self-help is as much a sham as are management gurus, which is no surprise because they overlap. Who cannot recall "Start with why?" or the "7 habits of highly effective people"? They play on your insecurities and promise silver bullets. If they don't work it is because you are, of course, deficient. You need another self-help book or follow this guy on Insta. Indulging all this self-help stuff is just another form of procrastination, instead of doing it you talk and read about doing it. It's just like learning Org-mode (no offense) to be better organized instead of, you know, organizing.
My waking call was, ironically, another management book "The Management Myth" by Matthew Steward (I think), which just showed me the ridiculousness of it all.
There's definitely a procrastination trap that someone has to be aware of, but I wouldn't say all the self-help/management is a sham. Much like people who get stuck researching, there comes a point where you simply have to act. There's also value in learning how to quickly pull items out of texts that you can use right now and discarding the rest.
I liken it to jiujitsu in a way. When I first started and knew nothing, I needed a lot of instruction and of course then practice. After years of that, I can now take a simple tweak to something I've been doing for years and suddenly it's much more effective. Finding those tweaks is the challenge, while also avoiding chasing silver bullets or bouncing to new thing after new thing and never getting good at something.
In my experiences, professional help is often just as much of a sham too.
Of all the self help books I have actually read, The 7 Habits is probably the one that had consistently been useful in actually navigating issues day to day.
And I read it probably closer to two decades ago.