So that was relevant until two months ago and is not right now.
Software have bugs, some are fixed quickly, other not. Dolphin (KDE file manager) also have bugs, it seems to crash for a number of reasons, also has scrolling issues, or bugs triggered by scrolling.
Do I say KDE is unusable because Dolphin can crash or has sometimes issues with scrolling. Nope that would be stupid. If I run into a bug with one among n components on a DE, I either report, fix it by patching it and supply a patch upstream, find a workaround or use temporarily an alternative component of that DE.
It appears the video in that post shows the bug, so, rather relevant?
The according issue seems to be[1], which has indeed been fixed two months ago, but as OP said was opened two years ago.
[1] https://gitlab.gnome.org/GNOME/gtk/-/issues/2971