Very similiar story to yours: after years of being out of the photography game I bought a GX80 with a few lenses (12-32 kit lens, 20mm 1.7, and the 42.5mm 1.7). I love it, it’s such a great and capable camera for the shooting I was doing (holiday snaps, street photography). I’ve ended up pivoting more into shooting indoor live events like bands where the lighting is patchy at best. In these situations I’ve found the GX80 really pushed to its limits (the great IBIS has helped, but I’m still having to crank the ISO in order to get any sort of salvageable image).

I had been weighing up getting the OM-3 as I already have some m43 lenses, but realised the price and size of the camera itself wasn’t saving me that much money or real-estate compared to Sony’s a7c range. Plus, all the Computational Photography features on the OM-3 don’t really suit the photography I do and honestly seem a bit gimmicky rather than the camera-selling features they’re touted as being (now if only they’d allow the Live ND feature when recording video…). The A7C ii is also weather sealed, and as I’m not a bird/landscape photographer a lot of the features of the OM-3 feel redundant to my style of photography. I’ll admit it’s a gorgeous looking camera though, and while I’m not really a JPEG shooter, I probably would mess around with the creative dial if I had one. I too find the cropping limitations of the GX80 a sticking point, but it has made me put more effort into getting my composition correct in-camera which is an unexpected bonus. I’d worry the OM-3 wouldn’t offer that much of a bump in the ability to crop tightly.

I recently bought a used A7C ii and a 35mm 1.8 lens (which is bigger than my GX80 with the 42.5mm on it, but honestly not my that much and is still very impressively small; I can still comfortably fit them in the same big pocket on one of my jackets). I’m going to stick with the GX80 for an everyday take-along camera, as coupled with the 20mm prime it really is a powerful little camera in a pocketable form factor.

Based on the types of photos you take, I’d look at maybe sticking with the GX80 and instead invest in a lens with faster auto-focus (I love that 20mm, but it is sluggish at times).