Hi all
my first post here as I’m quite new to nextcloud 
I’m looking for a possibility to perform user auth external (for example via a php script). I found addons like user_sql and user_backend_sql_raw but they do too much for what I actually want to achieve.
My goal is that the existence of user is still checked locally at my nextcloud and only the password is checked vs external. So all data for the user still come from local nextcloud database just password verification should be run vs external. I want to verify user passwords vs my Synapse Homeserver (Matrix) but without giving every Homeserver user a nextcloud account on my box.
So I’m looking for an option in user-management that allows setting an external auth provider instead of a user password. I still want to create/manage my users on my nextcloud interface just want to delegate password verification for some users.
Maybe there is an app already that does this which I did not find yet but user_sql and user_backend_sql_raw is not what I want 