only see 2020 in it.
Hexadecimal 20 is the ASCII space character. If your file contains nothing but 20 then it contains no useful data and no useful data can ever be extracted from it†.
is it maybe encrypted?
Encrypted data generally looks like a completely random sequence of hexadecimal values between 00 and FF. If your file contains nothing other than repeats of 20, it is not encrypted.
wallet.dat file is 180mb
Then I guess you might not have looked at every byte to verify that all are hexadecimal 20. I would use a program or script to see if somewhere in that 180 MB is any byte sequence other than repeats of hexadecimal 20. But the likelihood of recovery seems small.
† you could encode a small number, e.g. 7458 as a byte and a count of repeats but this is irrelevant in the context of recovering a Bitcoin wallet file
