From 6.8.1 back to 6.6.2 …

“Anki 25.01 Beta 1 revealed a bunch of regressions with the latest
Qt, and zero reports of improvements from it, so we’ll be better off
holding off on it for now, and perhaps reporting the deadkeys issue
to Qt once we’ve got a proper reproduction process.”

https://github.com/ankitects/anki/commit/cd1824165ffb0ba06f573e1e26f28078a35d93a9