uBlock Origin and mouse copy and paste works perfectly well in Firefox.

He made an edgy/abhorrent¹ joke years ago for which he apologised and Lemmy is even worse than Reddit so people still lach onto that.

¹ Whether it was just edgy or much worse than that I leave to the reader to decide. The joke was that he paid some guys in Africa to make a sign saying ‘Hitler did nothing wrong’ or something to that effect. This one of the things that likely contributed to adpocalypse on YouTube.

Switch to a non-buggy browser.

Yes. I’m just keeping the symbols file in home directory so that I don’t have to edit the system files. To change backspace you’d have something like the following I believe:

    key <BKSP> {    [ BackSpace, Delete ] };

My approach is to define custom keymap and enable it in xinitrc. Might be worth a try though I’ve no idea how that interacts with Wayland.