If you want to remove everything from the first opening parentheses to the last closing one, you can use a Quick Action Replace with regular expression for field _FILENAME, where you replace what is matched using
Regexp: ^(.+?)\s\(.*\)
Replace: $1
Usually I refrain from commenting on anything regarding handling of featuring artists 
It's been answered here on the forums countless times (for the Windows version) and it seems with each answer, a new edge-case or additional requirement pops up.
In your special case, where 3 artists are separated by underscore characters, you can use Replace with regular expression for field ARTIST, where you replace what is matched using
Regexp: ^(.+?)_(.+?)_(.+?)$
Replace: $1 Ft. $2 & $3
