So I tried all the official solutions and also windows re-install from iso, none worked! Only option was to make a bootable windows usb and start from scratch, which fixed it. I have had 2 major issues with Windows on this Dell PC, hard to tell if just windows, or a hardware/driver/Dell-based issue but not something I am used to with PCs in general - normally there are zero major issues. Using a second Microsoft account, to the logged in user, for some things did seem something MS was unprepared for, compared to Google at least.
I can not update or uninstall most programs in windows. msiexec can not be run. Even windows support has failed to help so far and has done all the usual checks. It appears to be some update to windows 11 that breaks Microsoft installer and clearly it is not all PCs affected. So is there something up on the Dell side?
msiexec issues - windows 11 installer broken on my G5 desktop