I ride with my kids and take a lot of photos. I also do a fair amount of nature shots as a hobby. I have some bigger Nikon dslr frames that i was lugging around because that's what I was using for work. I was carrying a ~25I pack with an insert to hold the camera, go-pro, some associated gear, plus enough tools, first-aid, snacks and extra water to keep the fleet moving. I seriously hated that pack. I was also really nervous about lugging around several thousand dollars in camera equipment.
Late last summer, I bought a small, inexpensive (relatively) Nikon z50 consumer mirrorless camera and lenses in the hopes to get everything into a smaller bag. It worked, though the 12L pack I'm using is too small for dad/photo duty (even after I bought the dog a vest and made her carry her own water to make room for lenses). I really appreciated this article as I'm looking for a new "goldilocks" bag as dave put it. The evoc 18 was on my radar along with a few lowe-pro options that I'm not sure I trust the build quality on.
As a down-sized option. I'm still not a huge fan of the tiny mirrorless, but I can't argue with the portability it provides and it takes excellent photos. I got more good photos with it at the end of last summer than I had in the previous 2 years, with a lot less staging, and very little editing. Largely because I was more likely to take it with me, and it was really fast to deploy. In using a larger z-mount with a dx sensor, the camera is able to pull off a neat trick where the included lens collapses into itself to make a body/lens combo that is smaller than many of my lenses. That combo fits into a hip-pack, no problem. I'm not selling photos, don't take a lot of low-light shots, and avoid anything more than basic editing. So, I don't miss the full-frame. I do miss my bigger lenses sometimes, and the build quality on the consumer camera isn't what I'm used to. However, it is small and crazy-light for something you can attach lenses to. It got me into a smaller pack while improving my shots.