Manipulating contained by brackets with and/or operations

I have multiple filenames that have content at the end and/or at the start with either () or [] parenthesis, sometimes both.
Examples:
004. In This Moment - The In-Between [OFFICIAL VIDEO]
025. Virtual Self - Eon Break (Blanke Remix)
045. [DnB] - Feint - Snake Eyes (feat. CoMa) [Monstercat Release]
I would have no idea what the script would be for this, I know that I will have to use the convert function and use %dummy%. %artist% - %title% for the simpler parts, but I need help with eliminating, or preserving/manipulating the content within the brackets

If you want to use the Convert function it would be interesting to see what data you want to import into tags or which data you have to recreate the filename.

I only have the filename and Artist sadly

It is much easier to create an unstructured string like the filename from structured tag fields.

Actually, I did not really get what you want to achieve. You told us what you have in the filenames. But then... do you want to get anything from in front of the brackets?
For that I would use for

%track%. %artist% - %title% [%dummy%
For

%track%. %artist% - %title% (%dummy%