Basically the transfer function on an erc721 interface (nft) cannot have enforced royalty payment otherwise it wouldn't support people transferring the token outside of a sale. Theoretically you could use some kind of interface standard or write up a different contract where users are forced to pay a royalty on any kind of transfer but then there wouldn't be a way to transfer it without paying the royalty and basically no nft trading platforms would support it because under the hood you have to transfer them the token so they can sell it on your behalf once a buyer is found.

FYI not trying to shill funny pictures but I do know a bit of solidity so maybe someone here is actually curious about the limitation.