tl;dr update:
Fedora KDE just starts software slower than Windows (10). It even boots slower than Windows.
Things like Brave Browser make it choke and die for no good reason, but the severity of this randomly changes.
.
Windows 10 and Fedora KDE have had this problem again these last months, among updates and tests.
Some times, the stutter is so severe and persists for so long that the computer just shuts down and restarts.
This problem persists even after I updated my PSU.