IMHO, this is more a choice overload [1] than a technical problem. You can pick whatever distro (another choice overload) and start using the default desktop environment, which is more than enough. Qt vs. gtk for desktop development? Use whatever you think will work for you, they are stable enough, and you can use almost any (even remotely popular) language under the sun for development. Java/Scala/Kotlin + Swing (or SWT) will also do the job (and let's put aside that Swing looks "old"; when you know what you are doing, you can make a modern looking-app with JVM stack as well, e.g. IntelliJ).
On Windows and macOS, you don't have any choice, so people usually see that as good enough because they can't compare it against alternatives on the same platform.
The other side of overchoice is that the community won't focus on maintaining, supporting, and optimizing one of them in particular, which does become a technical problem as old things fall into disrepair. Even sticking with Ubuntu meant having your entire UI change for no reason a few times. Whereas Mac OS is smoother than all the Linux DEs, isn't too different to use vs 1-2 decades ago, and you can search "how to do X on Mac" pretty easily.
Every Linux desktop user says "use what works best for you, we're all different," but I really don't buy that we're so different to warrant multiple competing DEs / window managers / whatever on top of the same OS.
On Windows and macOS, you don't have any choice, so people usually see that as good enough because they can't compare it against alternatives on the same platform.
[1] https://en.wikipedia.org/wiki/Overchoice