@Thorenzz For what it's worth, my Desktop PC takes roughly 30 seconds to get from Off to Login and 30 from Shutdown to Off, on this build (26220.8754), which I think is way too slow. I didn't see any performance difference to ...8690. My Laptop is on Dev, Home edition 26H2 26300.8758, shuts down...
Yes, mine is slow to start too. I log in and see that, after a 60+ second wait, not all Startup Apps have finished loading. I don't have many Startup Apps, so Windows is slow getting to them.
Updated my primary PC ok but the Event Viewer continues to show errors, which I thought related to use of the Local Security Policy editor but is not the case. It appears to be a known issue, yet to be corrected.