Is keycloak the right option for me?

Looking for advice:

I am interested in keycloak because I want an authn&authz server that can be safely accessed from the internet for a small number of users. It will provide services to exim (smtp), dovecot & roundcube, and potentially several websites. I am however not familiar with all the concepts and terminology in this area.

I can see that keycloak has features to store user credentials and implement authorization. However I am a lot less clear how I would connect it to dovecot, exim or a website without a lot of development work.

Am I using a screwdriver to hit a nail?

[Both dovecot and exim have auth functions including sql access and IIRC ldap. Currently I am using a mysql table for this.]

It’s worthwhile reading up on OpenID Connect, and the Keycloak Securing Applications and Services Guide

In general, Keycloak is a great tool for authentication (and in some cases authorization) for a number of applications. However, the issue is whether or not the applications you need to secure will lend themselves to protection with OpenID Connect (or in some cases SAML). If not, as you have observed, there might be a lot of development work involved.