Since projects of the same language often use the same tooling this makes it easier to clean up the whole directory by running something like this:

for d in ./*/ ; do (cd "$d" && somecommand); done

somecommand could be cargo clean if you’re in the Rust directory for example.

Depends on the exact system but there will be a method to switch to a newer release channel without reinstalling. Rinse and repeat every x years.

I assume you mean AVIF? Because AV1 is not an image (file) format but a video compression format (that needs to be wrapped in container file formats to be storable).