For the slow starting might check Task Manager and the Startup section, if something isn't recognized Disable it.
I just did an Update yesterday on a client's computer and got the same issue with KB5034441 and fixed it using suggestions found here:
DuckDuckGo. Privacy, Simplified.
duckduckgo.com
A Search on this site may give more information.
There's usually a small partition on the drive of less than 600MB that need increasing in size, double should work. I did find one thing to do, before resizing the C:/Boot/System drive run Error Checking followed by Optimizing.