This was a major update from Plasma 5.27 to Plasma 6.0, but also along with just about everything else, and was a 6.8 GB download for me.
It all went off flawlessly apart from one applet I use for transparent folders, which seems to still only be a Plasma 5 applet. But that is not a major issue really. My desktop is slightly more responsive now, and the compositor issue I had before has been sorted it (it used to create a 30 sec delay on some things like a rectangular screenshot) – so really happy about that.
I also had to readjust some window rules that I had set for my Conky window for position, transparency, etc but it was a minor issue where Plasma 5.x was not case-sensitive for Window names, so I just had to change ‘conky’ to ‘Conky’ with a capital C.
Looking forward to retrying Wayland again soon as well, as I suspect its random freezes were also related to that older Nvidia driver, which is now updated.