Only the old P2PK utxo are vulnerable because they expose the public key. So you only need to crack the ECDSA and calculate a private key from the public key.
Very quickly P2PK was followed up by P2PKH and P2SH so only hashes are exposed in utxo. This means that before you get to the public key you need to reverse a double SHA256 and ripemd160 hash.

I would worry about just about anything on the internet before I would worry about btc.