The upgrade/repair install I suggested on page 12 will keep everything intact -- apps, files & settings. Currently, what you download from the site will be Windows version 2004. So, if your currently installed version is lesser than that, you get upgraded. Otherwise, you get repaired. See your current version at "START, Settings, System, About".
If you get upgraded (& things seem worse), you may undo it at "START, Settings, Update & Security, Recovery, Get Started (under 'Go back to previous version of Windows 10'"...
But it lasts only 10 days. Also, it isn't available after a repair (just after an upgrade).
So -- make a Windows system image backup first. That lasts forever as a means to restore Windows to before the upgrade or repair. Want instructions? You should be doing that anyway.