Hey John, thanks for commenting! The only thing I can imagine it is, is that the id_rsa file isn’t formatted properly for openssl but works for SSH. Check your SSH key and make sure that it starts like this:
-----BEGIN OPENSSH PRIVATE KEY-----
and ends like this:
-----END OPENSSH PRIVATE KEY-----

If you run file ~/.ssh/id_rsa it might also reveal what the issue is, for example, in a .ssh directory I have access to, when I did file * I saw:

$ file *
config: ASCII text
config.d: directory
id_ed25519: OpenSSH private key
id_ed25519.pub: OpenSSH ED25519 public key
id_rsa: OpenSSH private key
id_rsa.pub: OpenSSH RSA public key
id_rsa_legacy: PEM RSA private key
known_hosts: ASCII text, with very long lines (613)

So, maybe you’ve just got a funky SSH Private Key which OpenSSL can’t interpret properly?