Xpra is known as "screen for X" : its seamless mode allows you to run X11 programs, usually on a remote host, direct their display to your local machine, and then to disconnect from these programs and reconnect from the same or another machine(s), without losing any state. Effectively giving you remote access to individual graphical applications. It can also be used to access existing desktop sessions and start remote desktop sessions.

(I knew about Xpra in 2021, but forgot about it.)

EMWM is a fork of the Motif Window Manager with fixes and enhancements. The idea behind this is to provide compatibility with current xorg extensions and applications, without changing the way the window manager looks and behaves.

XKB is broken in Xorg and will likely never be fixed, switch to Wayland