This Week in Plasma explains how we deal with post-release issues in the wake of Plasma 6.3—and how more testers are needed, and lists the UI improvements arriving in 6.3.1, and the new features lined up for 6.4.0. and beyond.
https://blogs.kde.org/2025/02/15/this-week-in-plasma-post-release-polishing/
if I could figure out how to submit a report for Wayland not working (mouse cursor existing but nothing else) with a specific monitor I would.
If the issue is KDE specific, the bugtracker is over at bugs.kde.org. Make sure to try and find out whether someone has already made a report.
There is a known bug about Wayland and ICC profiles in 6.3.