Hi everyone, I ran apt full-upgrade last month and accidentally deleted a couple packages that weren't supposed to be removed, due to me not paying enough attention. I could recover most of the system just fine, since most of the missing features and related packages were obvious to me. However, I still couldn't figure out why transparency is not working on KDE, both in Wayland and X. I suspected it could be a missing compositor, but libwayland and libqt6waylandcompositor6 (and related packages) are all installed (and that wouldn't explain why it isn't also working on X).
I have attached a screenshot to illustrate what I mean.
I would appreciate if anyone could help me figure out what package might be missing that is causing this issue. Thanks in advance!
EDIT: Thank you so much everyone! I finally solved my problem. I just had to replace libqt5quick5-gles by libqt5quick5 (non gles version).
Commandline: apt install libqt5quick5
Install: libqt5quick5:amd64 (5.15.10+dfsg-2+b2)
Remove: libqt5quick5-gles:amd64 (5.15.10+dfsg-2+b2)
If I am not mistaken, I used a Debian KDE live image from the official repository then switched the mirrors from Bookworm to Sid. The system went months without a single issue, then this happen.
Your suggestion will actually be my solution of choice if everything else fails: reinstall / and import relevant files from a backup that I already have.