If the point of using two hashes is resistance against people breaking one of the hashing algorithms used, you’re always going to have to pick more than one alg

If the point of using two hashes is resistance against people breaking one of the hashing algorithms used, you’re always going to have to pick more than one algorithm to get that benefit. However, I don’t think nesting the calculations is actually necessary: Blake2(msg)+sha512(msg) would give you the same protection.