Ditto, Ortlieb Backrollers are great! I’m amazed at how much can fit in them too, I can get a week’s worth of groceries in a pair of them. (Some bulky things like a cereal box get strapped on the rack between them.)

I really liked this one where the backpack straps and panier attachments are on opposite sides of the bag, the conversion is quicker (just flip the top flap over) and it’s more comfortable as a backpack than others I’ve tried. It got me through 4 years of college (overloaded with textbooks biking ~8 mi each way) but definitely started to show some wear, probably not quite as durable as an ortlieb but a great bag for $99.

https://banjobrothers.com/collections/backpack-panniers-banjobrothers/products/backpack-pannier-banjo-brothers