I find it weird that hash signatures are not commonly used since most asymmetric hash signature schemes (if not all) are provably safe as long as the hash function used is safe and they are also quantum-safe and very trivial to implement.

It is also extremely annoying that programs like gpg do not support the generation of large RSA keysizes such as 15360 bits which would require many more qbits in order to break (and since RSA 4096 and 2048 are much more commonly used, they might not even build a quantum computer capable of breaking them or they might create a much smaller amount of them).