aes256 is fine. This is a bit different for block ciphers and hashes. The very brief / simplified explanation: Block ciphers have a security level of their ke

aes256 is fine. This is a bit different for block ciphers and hashes. The very brief / simplified explanation: Block ciphers have a security level of their key size, so aes256 has a prequantum security level of 256 bit, which means a postquantum security level of 128 bit. Hashes however have - due to the requirement for collision security and the birthday paradox - a security level half of their size. Therefore for 128 bit prequantum security you need a 256 bit hash and for 128 bit postquantum security you need a 512 bit hash.