I tested freesync with my monitor and AMD GPU a lot, but I noticed there is a big difference of freesync between Xorg and Wayland.
Freesync on X11/Xorg = V-Sync or unreal sync:
Real AMD Freesync does not work on Xorg, but it is like V-Sync → Number of FPS is very changeable/flexible, but a fixed Hz refresh rate is not flexible on your monitor. (example: XX FPS game != 144 Hz monitor, 144 Hz is fixed.)
Freesync on Wayland = real sync:
Freesync works fine on KDE Wayland → When I play some official games on Steam, number of FPS runs the same as number of Hz (refresh rate of my monitor) Of course, this refresh rate is automatically a lot changeable, not always 144 Hz, but 30Hz ← XX → 144Hz.
XX FPS game == XX Hz monitor , that looks like real sync between FPS (on GPU) and refresh rate of the monitor
No tearing screen when you use any browser or other apps without gaming, a fixed refresh rate of your monitor is not changeable except gaming.
You do not need to manually enable Freesync on Wayland, because it has already been integrated into Wayland.