Yeah, so far as I know the only algorithm that provides an asymptomatic speedup (for AES or similar symmetric key crypto) over a classical computer is Grover's algorithm. That would reduce a 256 bit key to 128, which is hardly disastrous.

All of that seems to only be “medium” secure in face of future quantum computing.

“It's been estimated that 6,681 qubits would be required to run use Grover's algorithm to break AES-256 bit encryption.”

https://www.theregister.co.uk/2019/03/14/quantum_encryption_...

Not only that, there are asymmetric encryption algorithms not vulnerable to Shor's algorithm, we're just not using them yet (because they're slower and haven't been as well-studied as RSA or ECC).