W11 almost unusable

I installed the 25 version of W11 last October on a new PC as my old one wasn't 'qualified'.  Since then, I have experienced the following issues:

I The User Account Control pops up all the time telling me that Thunderbird, Firefox, Photoshop, File Explorer and others are trying to make changes to my computer. This happens even when that app isn't opened.

2 The troubleshooters don't work. If I click on one I get a box telling me that my PC doesn't have an app that can open this link. I am asked to choose an app from the MS store only to be told that aren't any apps for what I want to do.

3 My keyboard seems to go crazy so that I don't get the expected results. That could be with typing text where I get foreign language characters, or key presses in an app that do something other than they should.

4 Frequent reports of drives (SD cards or USB sticks) being faulty which they aren't.

Do I need to reinstall W11, or is there a less labour/time intensive solution to getting a working version of this OS?