Not Win
I don't know what the Supr key is I assumed it's the Windows key.
Do you use Mail, Calendar, Feeds?
Maybe, I have Feeds enabled but other than that I don't use those at all. I could happily do without those two feeds.
I've looked at my User Data folder with WinDirStat and most of are Sessions .bins, Cache (which should be empty because I cleared it), VivaldiThumbnails (deleted it manually just now, makes no difference in CPU usage) and History (which I had cleared, old history is not shown within the browser anymore but there's still a huge file).
2024-04-27_09-50-31_windirstat_WinDirSta.png