Filson will last 10+ years for sure

Filson is super legit. Again a little overpriced but man is that stuff high quality and might last for your kids/grandkids lol

I love all my filson items:

https://www.filson.com/best-sellers/dryden-backpack.html#sku=20152980-fco-000000074

Have heard great things about the yet bag actually:

https://www.yeti.com/bags/backpacks/crossroads-backpack-35.html

GoRuck has a big following but definitely that mountain style it sounds like you're trying to avoid, but kind of comes with the bifl territory often times:

https://www.goruck.com/products/gr1

Thule is a good brand as well and don't overlook camera bags, lots of small compartments in addition to the large main one:

https://www.backcountry.com/thule-aspect-dslr-backpack-1343cu-in