You must use the "Capitalize <Into Field> with exceptions..." version of the preset and specifiy in the preset (the Uppercase section or field)
what you want to remain in all caps.

Is this possible with any of the addons?

For example, I used the RegExp preset "Capitalize <Into Field>" on an album and it turned the Foo Fighters title "DOA" into "Doa", which is not desirable. I would like to go back and fix all these acronyms.

BTW, this could also include Roman Numerals, where "II" is converted to "Ii".