[Edited] The built-in Search and Replace tool allows regex searching (so you should be able to search for something that starts and ends with parentheses), but if that doesn't work try the Additional Tagging & Reporting Tools plugin.
This worked! Many thanks
<3
Steps for anyone who finds this later:
0. I would always recommend making a backup of your library in case you make a mistake.
1. Select all applicable songs (I selected the entire library to remove all instances)
2. Tools -> Tagging Tools -> Search and replace
3a. In "Search For" type what you want removed (e.g. Album Version).
3b. In "Field" I put "Any Field"
3c. In "Replace With" leave empty
4. Click "Preview" then check over all files, if you're satisfied Save.