My Win10 update 20H2 is 5 times slower than before...

Why does this update take so ridiculously long? And it's not the first one to do this. Most of the time the computer is on idle not doing anything. It's not frozen as the percentage will creep up every 30 mins. See this on many machines. There is no reason 1 update should take 8 to 10 hrs. Especially when most of the time the PC is doing nothing. Can install Windows 10 from scratch on a formatted drive in under 30 mins on a slow pc. Microsoft really drops the ball. These are clean business machines with very few apps installed. Maybe just office, QuickBooks and chrome.