kastentop2005
Did you enabled the kde-unstable repos?
Actually if you update your QT6 from the kde-unstable repo it does break, it cant be also recompiled against it. I faced the same issue.
I did simply block all qt5 and qt6 packages to update, when i enabled the kde-unstable repo.
Anyways, if you did this not please run “telegram-desktop” in your terminal and paste the output here