Linux isn't bad just because of apps, but because it's a chaotic experience for the average user.
Every app reinventing the wheel and fragmented, and every distro and developer fighting against the other rather than all coming together to cooperate and build something amazing and unified.
That's simultaneously a bug and a feature. Yes, Linux is in many ways fragmented and inconsistent when it comes to UI, configuration, etc. But therein lie the variety and the choices that a more cohesive OS simply has to forego in order to get shit done and to enable widespread support for users who are, largely, technically illiterate.
The "coming together" you mentioned, can only happen to the extent you want to see if developers are being paid and being told what to do. When that happens, the work is a job rather than a passion; then salaries have to be paid, HR departments funded, etc, etc. Then what was Open Source becomes closed and proprietary. At that point you have just another Microsoft, or Apple, or Google.
As a 15-plus-year user of Linux almost exclusively, I share your frustration. But what you and I want from Linux would be its death knell, so I swear and curse while simultaneously thanking all those hard-working devs who gave me a choice and allowed me to throw off the yoke of Windows, MacOS, and stock Android.
Anytime a user is told, RTFM, there's something fundamentally wrong with the usability and perhaps the entire OS.
If that's the case, then I've never used an OS that doesn't have "something fundamentally wrong" with it. Even trying to do stuff on my wife's Windows 10 computer has me scratching my head, and Windows 11 is worse. Also, I'm in the process of converting a Pixel phone to LineageOS; getting around the native Android OS on it is like playing pin-the-tail-on-the-donkey - and I've been using Android of one flavour or another for 12 or more years. So I'd say that mainstream OSs aren't what they used to be, and in fact they never were.