Best business cc/setup for my spend?

Hey all, this is on behalf of my parents but question still applies. My parents recently bought a business which requires a fair bit of spend at a small group of retailers so I wanted to see what could be optimized in terms of cashback or points

Between the following retailers, they can put 5k-8k per month on the cards: Dollar General, Aldi, Sams Club, Restaurant Depot, Costco a few wholesalers which would probably not be coded into anything special

I don't really care about miles since we don't travel often but since Amex and Chase points can be worth over 1 cent when redeemed for travel, I can take them as well.

They're open to having a credit card setup in case different cards are better for different stores