We've had a number of folks migrate from Keycloak due to some of this clunkiness, but I do know they've done some major overhauls recently (moving to Quarkus amongst other things).
It also used to be super resource intensive if you have a large number of realms (which is what Keycloak calls tenants and Cognito calls user pools). From this 2022 link, more than 100-200 can cause issues: https://github.com/keycloak/keycloak/discussions/11074
We've had a number of folks migrate from Keycloak due to some of this clunkiness, but I do know they've done some major overhauls recently (moving to Quarkus amongst other things).
It also used to be super resource intensive if you have a large number of realms (which is what Keycloak calls tenants and Cognito calls user pools). From this 2022 link, more than 100-200 can cause issues: https://github.com/keycloak/keycloak/discussions/11074