This is convoluted and won't work. The first problem is the assumption that you can create a spendable UTXO by embedding the signature in the output script. That runs into a circular dependency, because the sighash commits to the transaction that defines the output in the first place.

> We can start from "pubkeyA", allow using any "signatureB", apply public key recovery, and reach "pubkeyC"
I’m not sure what this is supposed to mean. In ECDSA, a signature lets you recover the public key that produced it. So unless "pubkeyC" is just the same as "pubkeyB," this step doesn’t make sense.