Thank you, I am glad to see the competing proposal. I will add again that either CHAINID or VALID_CHAINID could be implemented from the other using a trustless contract.
i.e. If CHAINID opcode is available then a trustless VALID_CHAINID contract can be deployed and everybody can trust that it operates the way that VALID_CHAINID is specified (when it is specified) to work.
And vice-versa, ff VALID_CHAINID opcode is available then a trustless CHAINID contract can be deployed and everybody can trust that it operates the way that CHAINID is specified to work.
If there is any more interest in this point, I’ll be happy to discuss on the other thread at EIP-1959 Valid ChainID opcode.