Yes, thanks, that you mentioned that someone could try to make an NFT out of it. We don't have a classical NFT here, but this 'signature chain' works and could become something

who knows? Mabe we have something like 'cryptopunks' in the making. At the beginning people didn't understand blockchain & NFT too.
Yes, right, I think I understood your basic idea, this is not a classical NFT, it will be a new type of NFT that differs from the previous one, based on the signature chain and not just the old address. Perhaps this new style will be popular with Bitcoin fans in the future.
I read the discussions between you and franky1 it was really helpful to clarify the idea, you can make use of these discussions and objections to develop the idea later, if you succeed in that maybe this is the start of a new and unique type of NFT.
good luck