Generate JWKS from X.509 Certificate

I already hold an X.509 digital certificate and I now need a matching set of JSON Web Key Sets (JWKS) built from it so I can feed the keys into an OAuth / OIDC gateway. The keys must be created for the RSA algorithm only; I do not require EC or HMAC variants at this stage... (Budget: $30 - $250 USD, Jobs: API Development, Cryptography, OAuth, OpenSSL, Security, Software Development, Software Engineering, Web Security)