A sock. Put your new iPhone in a sock.
Just messing with you man. You can see how many people are upset and frustrated, learning their new phones scratch too easily. In one of your post you mentioned a coating over the top that apple apply. Maybe we are all experiencing that winch is scratching??
Back to your question, my advice wouldn’t be any different to yours. It’s just that I’ve never liked screen protectors, actually I hated them. But now it seems we need them to protect these very delicate phones. Apple designs beautiful phones, and markets them by showing us the phones naked. We never get to enjoy them that way, unless we are using them in bed, holding it above a pillow encase it fell. Best phone I’ve ever had was the iPhone X. Dropped it from a roof, no issue, scrapped it agains tiles, no scratches. Just put the iPhone X screen on the 12, problem solved.