I’m facing your EXACT problem and have made just about as much progress as you are. Only difference is I’m running Garuda instead of EndeavorOS. This definitely seems to be a problem with KDE Plasma’s Wayland compositor.
Could you tell me your system specs? This might be a hardware related issue perhaps related to NVIDIA since we all know how much Wayland loves NVIDIA, Here are mine:
Laptop: Asus Zenbook 14
Model: ZenBook UX434IQ_UM433IQ
RAM: 8GB
CPU: AMD Ryzen 7 4700U with Radeon Graphics
GPU: NVIDIA GeForce MX350
Might I also add that what really made me decide to switch Window Managers/Compositors was after I tried to edit my desktop, and after removing a single panel, my RAM usage rocketed into oblivion and just nuked my OS into a forced restart.