Being merely an enthusiast in the ever shrinking group of people who don't believe a smartphone suffices to take good photos on trips, I'm in the small & light camp. Until very recently I carried a trusty DMC-GX1 which was very portable but was really starting to feel too limited, so I went for the OM-5. Slightly larger and heavier, but not by much and still fits in an ancient but durable Samsonite bag I still have from the film era. Sorry, this won't be of any help for those wanting to shop for a new bag, unless you include antique shops in your shopping trip.
Even with a 100-300 lens mounted the OM-5 still fits in this bag (only just). I like this bag because it easily fits in a backpack and looks inconspicuous.
As an illustration of trying to use a smartphone versus an 11 year old camera for photographing a far away building on a hillside at night… The phone is a mere OnePlus Nord, but I doubt the more advanced ones would fare much better. The latest Samsung AI thing might hallucinate a set of candles or so from this kind of sensor reading.
Many are curious what others have, myself included. I havent been down the "backpack" road yet but I will some day. For now I like my shoulder strap with the bag under my arm. Inside this bag you see a 7DII, 70D, EF100-400 II, 10-18 EFS, and 18-135mm EFS. Sometimes my Flash and SP 150-600 ride in a different bag if I need them. The bag is a discontinued Canon. Maybe the Professional 1EG. I see them on e-bay yet.
Thanks for starting this thread, I am sure it will be popular.