>>4153506Aside from an additional small bag to maybe pair as a form of quick access with a backpack for carrying the bulk of your stuff when you do bring a good amount, there are various camera straps for different carry styles, or things like the Peak Design capture clip which will let you clip your camera to something like the fronts of your backpack straps via a mounting attachment using the tripod screw hole, so you have quick access to it on your chest.
If you do use just a sling for lighter days, nicer slings will usually have better thought out ergonomics, straps with better weight distribution, and by being critical of what you truly need to carry and wearing it tight to your body, it keeps weight down and centralizes the load a bit more, so it mitigates some of the potential downsides.
For general backpack brands: North Face, Osprey, Mystery Ranch, Patagonia, Goruck, Timbuk2, Chrome Industries, Evergoods, Tom Binh, Arc'teryx, Cotopaxi, Topo, Able Carry, and Bellroy all come to mind as having quality products at various price points and styles. Many of them will also offer padded or unpadded slings, and some make dedicated camera backpacks in addition though you'll often get something more comfortable and rugged for cheaper by not buying something just for cameras and just using a padded insert for protection instead. That said, brands I hear good things about or have used myself for camera-specific bags include Shimoda, Tenba, Think Tank, Mindshift, Lowepro, Hex, Brevite, Wandrd, Peak Designs, Pgytech (one of several brands doing low cost PD knockoff products on Amazon). Get ones that open up for camera access on the strap side if security is a concern.
Of the backpacks I've personally used, I've found the harness systems used by North Face and Mystery Ranch (many consider Osprey up there too) to be the most comfortable overall, but all of this is very personal based on your body and use case. Try stuff on, ideally with a comparable load, if you can.
