This will be a short one!
When working on the mod for Chained Echoes, on the WSGF Discord I said "Fixing all the other Unity games should be like a walk in the park after this one".
Going by We Are OFK, that was definitely not true for all games, but addressing Valfaris was quite straightforward.
I installed it right after the request on WSGF and I soon found the code responsible for its resolutions and the black bars, so I just patched out the offending parts and did a bit of testing. Now this retro-style side-scroller game has no black bars either at the gameplay or the cutscenes. Both of its CRT filters are supported as well.