Can we use keycloak to integrate with REST OAuth-2.0 API?

Hello everyone!
We have two projects with two unrelated auth systems and we want to get rid of one auth system and transfer two projects to one auth. Our goal is client control and SSO for two systems. Main auth system is OAuth-2.0 compatible and has device, OTP, password auth, userProfile control.
Can we integrate keycloak with our main auth system by REST OAuth-2.0 API?

Thank you!