I’d also like to know. Sellers can know when you’re using a popular VPN service or have DeGoogled, but I don’t know how they may use that information. Perhaps they’ll try to punish you into submission by jacking prices to the moon or refusing to serve their website altogether. Reddit and some other sites already block VPNs.

There will never be a silver bullet, because this will be an endless arms race between sellers and savvy consumers.