p.1 #4 · Recommendations for a Shoulder bag for 2x bodies with lens mounted on each
There are messenger bags and/or soft brief case type shoulder bags. Might be a place to look, they are often sized and sleeved for laptops. from there check for sizing to fit the camera gear, too. My laptop bag is set up with several full zipper sections and some dividers and might not fit the cameras They tend to be set up for letter/legal flat items, not lots of front/back expansion.
Added: Consider camera inserts if looking to non-photo bags. Take the gear with you, if possible, when shopping. It helps with fit checks. I've found some bag descriptions along the lines of "fits up to two mirrorless bodies and three lenses" to be wildly optimistic at times.
p.1 #7 · Recommendations for a Shoulder bag for 2x bodies with lens mounted on each
I just bought a Think Tank Retrospective 5 V2.0. I like the bag a lot. It's a messenger bag that's kind of low profile. I think the 5 would be too small for your setup. Maybe the version 7 would work? They have larger bags as well.
