Upgrade isn't likely to help. If KDE is struggling on 6@32, you have something going on that 16@64 is only going to make it last twice as long before choking.
wail till it's slow
Check your Ram / CPU in top and the disk in iotop, hammering the disk/CPU (of a bad disk/ssd) can make kde feel slow.
plasmashell --replace # this just dumps plasmashell's widgets/panels
See if you got a lot of ram/CPU back or it's running well, if so if might be a bad widget or panel
if it's still slow,
kwin_x11 --replace
or
kwin_wayland --replace &
This dumps everything and refreshes the graphics driver/compositor/window manager
If that makes it better, you're likely looking at a graphics driver issue
I've seen some stuff where going to sleep and coming out degrades perf