Accepting Bitcoin as payment method

Hello everyone,

In my still young and small business I would like to offer on chain Bitcoin transactions as a payment method. My business works like this: Costumers see my product online, make an appointment with me and then come by to check it out and eventually pick it up. The bill is paid on the spot, usually in cash, paypal or bank transfer. My concern now is: I can't really let the costumers waiting for three blocks to pass by to make sure the transaction is valid, in case I accept btc. Also do not want to let them go with the perhaps unpaid goods. Payment in advance is also rather difficult since they will need to come by first to make a buying decision. And since the product is not something you would need to buy regulary, lightning network would not be an option, I guess. What do you think? How can a small business like mine be handling this properly? Thank you so much in advance!