Does hotel check-out have to be done in person?

No.

No, it’s not that strict. It can be a friend or relative. Your spouse will take your room card to the front desk to check out.

Check-out is not so strict, because when checking into the hotel, you must go to the hotel with your ID card to check in. The hotel already has your record. When checking out , just you or someone else needs to return the room card to the front desk.