I see from an earlier post Windows 10 / Gimp 2.10
Have you checked the 'mode' do you get anything like this, where it is disabled?
Very rarely does reinstalling Gimp make any difference, all the settings are held in the Gimp profile.
C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\ Rename that to disable it and start Gimp up to make a new default profile.
See if the path tool works with a 'blank' canvas. If it does work, start (slowly) moving resources, brushes plugins scripts, over from the old profile checking that all is working as you go.
Have you checked the 'mode' do you get anything like this, where it is disabled?
Very rarely does reinstalling Gimp make any difference, all the settings are held in the Gimp profile.
C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\ Rename that to disable it and start Gimp up to make a new default profile.
See if the path tool works with a 'blank' canvas. If it does work, start (slowly) moving resources, brushes plugins scripts, over from the old profile checking that all is working as you go.