These are based on solutions from the Rename - remove everything in bracket Help & Support thread.
It deletes all () &  brackets with its contents in a file name
Remove Autogenerated Brackets
The second one was done by me.
It deletes at () bracket at the end of a filename that are produced by Opus if the name already existed.
foo (3).bar =>
There are two versions of this preset. The Opus 12 & above version lets Opus handle the file extension automatically, instead of the regexp having to deal with it.