SHA<u64>, let's for the purpose of this example say the u64 is set as the integer 256.
This hash function will always return a hexadecimal of length 256 bits.
Likewise for SHA512 and so on.
Rookie mistake...
First off, have a skim through
https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.180-4.pdf
Furthermore, what is SHA-1 going to return? A single base16 bit? Have fun decoding that.
The key to understanding this, is to know that a hash is in binary and the hex string is just an encoding of that.