If you want to use Keycloack as authorisaztion solution in Appmon (like LDAP) than not.
Here you have more detail about supported technologies. In general only LDAP can be used for such tasks.
If you want monitor keycloak you will see it as a process only, not on transaction level. So from that point, yes you will have some metrics. If there is option of collecting of extra Parameters you can always create OneAgent plugin.