I notice that if I copy text from either Dino (an XMPP app) or Nheko (matrix client) and paste it into either Ungoogled Chromium or Firefox, the whole browser and all tabs freezes.

WTF. Firefox and UC both claim to have containerized sessions. Every tab should be separate and immune from interference by the others. But if I paste something from either Dino or Nheko into one tab, it fucks whole fuckin’ kit and caboodle. Browser is dead frozen. Must be killed.

It’s likely some kind of Wayland fuck up. Probably some botched interplay between wayland and X11. I did not really dig into it.