Comment by Chu4eeno

It sounds like Wayland.

When you decide to suddenly stuff some of the most complex pieces of software together (the X server and the compositor which sometimes also double as a desktop shell) into giant codebase/process with seemingly no proper plan or roadmap and make up the specification along the way (or just don't, wayland still has no proper XACE replacement, so kiosk tooling etc. is ad-hoc), you get Wayland in its current form.

Rant over; if you want to actually find out what is making stuff stall, maybe try bpftrace, DTrace or SystemTap (depending on what your distro ships and what tooling is more familiar/suited to you)? Or just run `perf top` and see if anything stands out.

For the boot run `sudo systemd-analyze critical-chain` and see what it is waiting on. And be ready for the nightmare that is the systemd "design": https://blog.darknedgy.net/technology/2020/05/02/0/