Very difficult to give advice when the advice is generally ignored.
Set up my Win10 VM with a second hard drive ( E: ) and installed Gimp 2.10.6 - the one from gimp.org on it.
Gimp same as always creates a user Gimp profile, Gimp 2.10 creates one in your user section "../AppData/Roaming/" This is a hidden folder so as a Windows user you need to know how to access it.
Why did I ask for a screenshot of
Edit -> Preferences -> Folders -> Plug-ins? Just to confirm that 1 ) it exists 2 ) Location.
Should look like this.
However, I see you are back to putting the plugins in the Gimp systems structure, so I will do that as well.
Starting Gimp 2.10.6 up and applying heal-selection, does it work. It does here.
My conclusions. Nothing actually wrong with the plugin files. The Gimp program installation location has nothing to do with your problem.
It could be, something strange with non-english installations, There is another user with seemingly problems.
It could be, a jumble of plugins, producing conflicts.
It could be, the way you use the filter.
It could be some strange attribute of the actual files.
What can you do?
You could use a second version of Gimp, a portable version that will run from your second drive. One already mentioned
http://www.partha.com and another
https://samjcreations.blogspot.com/ Each of these has its own section for user plug-ins to prevent screw-ups.