I'm one of the most adamant proponents of using a bike... but groceries shopping is kind of the worst example in my opinion? I usually have a relatively roomy

I'm one of the most adamant proponents of using a bike... but groceries shopping is kind of the worst example in my opinion? I usually have a relatively roomy bag with me that fits a lot of stuff when I go on a weekend trip but falls completely short when buying groceries. Same for other backpacks I own. Or it could stain the bag. Everything is huge and bulky, especially drinks and cans or even just vegetables for mor than one perseon. Do I really need 2 baskets or 2 extra panniers?