Hi.
I have made a few erroneous changes to the keyboard shortcuts and now I am unable to use almost any keyboard shortcuts.
This is really bugging me as I have been using gimp as a beginner for a while and keyboard shortcuts are very handy.

Can please someone point me in the right direction ? I tried to uncheck "Save keyboard shortcuts on exit" but that did not help.

You need to remove/rename your menurc file in your GIMP profile, so on Windows that is at C:\Users\username\AppData\Roaming\GIMP\2.10\menurc

With GIMP not running, rename the file, re-start GIMP and you are back to defaults.
You could alternatively edit the file to correct the mistakes if you're feeling adventurous

Thank you very much. This has bugged my life for a while.....
In my case the file was under C:\Users\username\.gimp-2.8

Edit>Preferences>Interface has a "Reset keyboard shortcuts to default values" button (at least in 2.10).

Thanks ofnuts. Gosh, who would put "keyboard shortcuts" under "Interface" ? It has nothing to do with the interface.