If your Windows 11 system has issues with booting, crashing or behaving strangely even after re-installing your apps etc then there maybe a fundamental issue with the OS itself, this might include even refusing to boot-up.
If that is the case (and even if not, you should prepare) WindowsReport.com has a great article that might just save your OS and your sanity. All you need is at least a clean 16Gb USB drive available.