Could also just be player incompatibility not all discs blu-ray or DVD work on all players. You should try it on another unit I don’t know what would happen if it doesn’t play on another device. Of course it has to be capable of playing NTSC region 1 discs you say the player you tried it on does.

Edit: I see you tried it on several players. That is so weird.

I have a cheap 40 dollar player that does all region it plays my Pal Return of the Jedi disc fine. But to be clear I haven’t played my US discs for a long time 2006 most likely, I hope they aren’t coasters.

If it is disc rot, I hope the seller will offer replacements or your money back.