They always rant about Wayland, systemd, Pulse/Pipewire, devops, dkms, quic, zfs, etc.
Some of these things are not like the others.
Systemd is an abomination and should die horribly in a fire. I've written extensively on this. It not only breaks every software design principle I can think of, but presents an attack surface by which almost all of the public Internet could be brought down simultaneously.
Pipewire does not seem particularly problematic. I've not switched yet, but purely because of inertia; I have no objection to doing so later once I have time.
Devops, dkms, quic, and zfs seem to be great for many use cases, though not necessarily all. I haven't had a need for any of them except devops, and then only at work, and then only to the fairly limited degree that is possible given our regulatory compliance and security stances.
ZFS ships with a license that is incompatible with the GPL, and that is their choice, but you can build and install it yourself if you're technical enough to understand why you'd want to. You just can't then redistribute it.
This leaves Wayland. The difficulty is fairly obvious. Its design does not allow it to do some of the things X did, and for some uses cases that's just fine and in others it's kind of a show-stopper, unless we can find another way to do those things. Reliable screen locking, network transparency, XFCE4 support, and not having apps crash if the Wayland process crashes, are a few items on my wish list.