I used a messenger bag for about 10 years loaded with heavy books and it has messed up my shoulder a bit. I can't carry anything for more than an hour without it hurting really bad now. It can't be good for your back either. For that reason, I'll never recommend a shoulder bag of any kind. It's probably fine if you don't have much weight or you limit your time with it, but with all that gear I might steer towards a two-shoulder bag. In my experience, there's no such thing as a bag that's really easy or convenient to access all your gear quickly and is also comfortable to carry around. I have always found it easier to just quickly dump the bag on a table or even the ground, switch my lenses, zip it up and throw it back on than to try to fiddle with holding the bag with your 3rd arm while you try to change your gear.
The best I've found for this is my F-stop Ajna with medium ICU. I can carry my body, 70-200, and 2-3 other lenses with ample room for a tripod and other peripherals or personal items. It's super easy to dismount, open up, direct access to everything through the back, zip it back up, and throw it over your shoulder again. Great support, comfortable, and well-made. I highly recommend it... if you can afford it. I think all-in I was around $300 for it which is admittedly pretty steep. But I justified it based on the value of the gear I was putting inside of it, it's comfort and quality, and unmatched feature sets.
You can probably get something 85% as good for a bit cheaper, but I really like my Ajna and am happy with the price and performance.