@Whippie
Going back to your first post quote: I'm using Ubuntu 20.04 with Gimp 2.10.34 and Python 2.7
That looks like it is the flatpak version. A test installation and it does look like there is a problem with the default plugins folder.
Regardless, make a new "easy to find" plugins folder and put your plugins in that. Use Edit -> Preferences -> Folders and add that folder location in the plug-ins section
This video for the why's & wherefore's https://youtu.be/loN4OQ53hDc long one for me, four and a half minutes.
Going back to your first post quote: I'm using Ubuntu 20.04 with Gimp 2.10.34 and Python 2.7
That looks like it is the flatpak version. A test installation and it does look like there is a problem with the default plugins folder.
Regardless, make a new "easy to find" plugins folder and put your plugins in that. Use Edit -> Preferences -> Folders and add that folder location in the plug-ins section
This video for the why's & wherefore's https://youtu.be/loN4OQ53hDc long one for me, four and a half minutes.