Have to plug my new bag, it's been working great. Hazard4 Evac Rocket. It's a sling backpack with a very wide, cushioned, and solid strap. It's also much taller than it is wide so your weight load is spread out more evenly diagonal across your back.
There's a secondary stability strap that connects to the main one to keep it from slipping down and around accidentally. It's very easy and quick to unclip that strap and swing the whole bag around to your front, without taking it off. This allows you to stay seated on your bike and access the whole pack without taking it off, which is great for me.
It's well built with a warranty. Lots of pockets and molle straps for adding extra pouches. Also has a hydration reservoir pouch.
Hazard4 Evac Rocket Sling Pack