[456hdsaq234g]

Can you confirm that the reason the password is forced is the PKCS12 (pfx) import has flagged the key as requiring a password every signature? (and it cannot be disabled).

I believe you can use mimikatz to forcibly strip the strong protection flag from the key. Microsoft says this is normally not possible, yet here we are. You might want to try downgrading the strong protection flag on the key material, it may allow for automated signing.