How should I replace these words in brackets and the word before it?

[bbingr]

I have multiple text strings containing A(a), B(b), C(c), etc.



A and a are related over and thousands of these are in one sheet.



I want to replace A(a) with a and B(b) with b, so on. Any thoughts please?






EX:
Optimizer Mode(OM) -> OM

Home Snoop(HS) -> HS

 

[bbingr]

I used the term "replace" because there are other texts as well, so i cannot just remove every text except the word in brackets.
EX: I love Optimizer Mode(OM)!