This is exactly what happens. Actually the whole Wayland/xorg thing is not necessary, simply exiting a Wayland session and starting a new one will probably have the same effect, might depend on compositor. But it doesn’t help knowing that it’s the cause, I’ve known it for years, no closer to a solution. Obviously closing the tmux session and starting over is a “fix” in the same way that turning the machine off and on again is a fix. Kinda defeats the purpose of persistent tmux sessions.
Synology supports docker containers. Just run jellyfin.