I need a flatpak program (Ardour in this case) to see some music plugins (which are installed in /usr/lib/lv2) but I couldn't make it to see those directories.
I found this answer and tried FlatSeal but it didn't work either:
The triangle says "Changed by the user". I guess it's a warning mechanism for not changing too much or knowing what you have changed.
I tried the command line approach in the above link but it didn't work either.
I'm using PopOs which is Ubuntu based. Deb version of Ardour isn't available in shop and it's hard to compile Ardour from scratch. Also I had similar troubles with other flatpak programs in the past (ex. Unity not seeing VS Code).