I took some photos at an event and I need to go through them and get rid of the bad ones (eyes closed, things in the shot, out of focus, blurred etc.) I’m not a pro photographer so no idea where to begin with photo apps. I’ve used RawTherapee and Gimp a bit.
What app will let me quickly browse the photos and handle (delete/tag) photo formats together (both the RAW and the JPG)?
Darktable is what you want. You can also use digikam
Another suggestion for Darktable. It handles this case of mixed types transparently. It’s a big thing to learn, but extremely powerful and capable, and you don’t have to know all the corners of it, just enough for your workflow.
Capture One has a free 30 day trial IIRC. It’s great for doing this kind of thing, if you put caps lock on you can hit keys 1-5 to rate and it will auto advance.
Digikam. It supports grouping (or stacking as it’s called in Lightroom) by filename, so you can auto group RAW and JPG. It has hot keys for flagging rejects/approvals during initial inspections and review, so you can just fly through them.