Most of the transactions I do are with Bitcoiners who are already familiar with the Bitcoin payment process. I have not figured out how to onboard anyone without Bitcoin already in any quick and smooth way. Even when people have cash app it seems like there is always some technical snag for them to buy the Bitcoin then send a transaction.

I use phoenix wallet for lightning transactions and if the price of the item is in dollars I let Phoenix do the conversion to sats when building the invoice. I write pertinent information in the memo on the invoice to keep track of inventory.

I don't have an on chain wallet that I like right now. I was using muun but I would like something with better utxo management and paynym support. I'm thinking samurai might be a good wallet but haven't used it yet. That being said I very seldomly find someone looking to pay on chain for any of my products face to face.

I heard that breez and zues have pos functionality but I haven't had the need for it so I haven't looked into it. Might be worth checking out.

If you have any other questions or want me to elaborate or clarify anything I'm happy to. Earning Bitcoin is the best way to stack hands down from my experience.