iPhone SE (2nd Gen) 2020 iPhone locked to owner

Best to return the phone for a refund.

The original owner is the only one who can remove the activation lock. Otherwise, the phone is useless.

Please do not buy a used phone unless you know the owner and they are willing to let you return it for a full refund if you are not satisfied.

Only if the person you bought it from releases the lock. If they listed it as a locked phone you have lost your money, if they didn't report a fraudulent sale to eBay. If you do hear from the owner send them this link: What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support