Camera bag design seems to have moved on from that, and a sling design seems to be more popular.
The sling lets you swing the bag from your back under your arm to in front of you. There is a zipper towards the side that lets you securely access the camera and accessories.
So pretty easily you can get your camera out, or later put it back without removing the backpack.
My solution is I have a PD 30L as with dslr, 200-400, macro, 24-74 lens two straps are nice to have purely due to weight vs sling. The side access is clutch.
https://www.incase.com/products/dslr-pro-pack?srsltid=AfmBOo...
Lowepro also has day/overnight/carryon backpacks, so you can carry some DSLR gear, laptop, change of clothes, and toiletries, all in one bag.
I still have one LowePro day backpack that I repurposed as engineer/startup briefcase. It fits a huge laptop and misc. stuff for working late hours, and has a DSLR door in the side, so you can slide one shoulder strap off off long enough swing it forward like a sling bag, for quick access to a good camera for serendipitous shots.
Regarding real sling bags, I personally wouldn't use for lengthy carrying of heavy stuff, since it's asymmetric left/right. I even got rid of my grocery canvas tote bags, and use an old backpack for carrying home groceries.