I, and I'm sure I'm not alone, have been on the unachievable search for the "holy grail" of camera backpacks. I've been through a ton, but am now "down" to 3. A F-Stop Guru for work, a Wandrd PRVKE 21l for travel and a 20l Peak Design for "stealth" city trips.
F-Stop Gear Guru
I've used F-Stop Gear for many years and for the most part they've work really, really well and held up great. They are my favorite packs to work out of which is why I still use one for my Interior Photography work kit.
I very much like how they lay down on their back and open, which makes for an easy working bag in various conditions. I typically carry two Canon EOS R Bodies, the 17, 24, 45 and 90mm TS-E & 16-35mm lenses, my Camranger, 1.4x extender, batteries & 11" iPad Pro.
Wandrd PRVKE 21l
The Wandrd PRVKE 21l replaced a well worn F-Stop Gear Guru UL as my primary travel bag for only one reason, size. It just fits, according to specs, the carry-on limit for small European airlines. It's a bit more finicky than my old Guru UL but the size and efficiency are better, in my opinion. I usually carry my Hasselblad X1D & Mamiya 645 Pro bodies with 35, 50 PC, 80 & 150mm lenses and my Lee Seven5 filter kit. Plus for travel the iPad, earbuds etc.
Peak Design 20l Every Day Backpack
This is really a special use pack. And although I'm not a big fan of side load packs it has one feature that I really like, I can carry a tripod inside the pack. Typically I'd carry my Gitzo tripod with RRS head and either a film or X1D kit. Usually for trips to the city to shoot architecture.
Although I'm always keeping an eye out for the next best pack, It'll take quite a bit to "dethrone" my current ones.
Bill