they don't know necessary who are you and what are you buying. I don't think also for big shops with many customers that techonology and reliably do instance segmentation - this is not face id.
Doesn't stop the stores from posting clips of you embarrassing yourself online and your acquaintances giving your name away for clout.
They don't, but there is a significant chance that their "security solution" uploads all the data to a cloud provider (Amazon, Google, Oracle) which will be more than happy to analyze the data for them.