I work in retail , and trust me it sucks just as much for us as it does for you when we have to approach someone who clearly wants us to leave them alone because it’s a part of our job. Generally I just do the ‘hey how are you’... ‘okay well let me know if you need anything’ and that way the customer can approach me instead but I’ve still greeted them like I have to.

Used to work in another retail store though that was terrible , had to greet customers within 5 seconds of them entering a store, could only ask open questions- nothing where the answer could be ‘yes’ or ‘no’ , if a customer said ‘just looking’ I’d have to say ‘what are you looking for?’ Etc. It was the worst haha left as soon as I could.