As far as bento box/bags go, I’ve used an x-lab: https://www.xlab-usa.com/stealth-pocket-300.html and also the Torhans: https://www.torhans.com/collections/aero-bento/products/bentox
The Torhans looks nicer, but it’s been a struggle to get it to fit the frame the way I want it to. It’s got a soft rubber top so there’s no need to zip open/closed anything to get to the stuff inside. Overall, I’m not in love with it, but it’s what I”m using today.
The x-lab has a zipper that got a bit gummy from leaky gels, but when the zipper is clean, it’s really easy to get stuff in and out of. I’ll probably go with the Torhans for my “test” half distance this May and then decide if I go back to the X-lab or not.