Keeping Multiple Qualities

I’d like to keep both Web-DL’s and HDTV episodes. Recently WebDL’s have a 24hz issue where they have jerky frames every 2-5 mins or so. I’d like to have the HDTV copies as a backup in case the episodes are impacted by that.

I’d also like to keep Web DL’s even if Blu-ray encodes are downloaded because they’re much better for mobile devices.

Anyway to do that currently? If not feature request.

No we don’t.
But you might be able to use the recyclebin directory feature. Sonarr puts the upgraded files in that directory.
See Settings -> Media Management -> File Management -> Recycle Bin.