I implemented authentik for my immich server just last week and I can confirm that Immich will merge the accounts as long as they have the same email address. My other services I had to configure to use email matching. Paperless-ngx needed an environment variable added to allow it, and Grafana I didn’t even have a user created for myself, just used the default admin account.
Jellyfin doesn’t support OIDC without a 3rd party plugin, so I haven’t set that one up yet. I also don’t use nextcloud, so can’t comment on that.
I implemented authentik for my immich server just last week and I can confirm that Immich will merge the accounts as long as they have the same email address. My other services I had to configure to use email matching. Paperless-ngx needed an environment variable added to allow it, and Grafana I didn’t even have a user created for myself, just used the default admin account.
Jellyfin doesn’t support OIDC without a 3rd party plugin, so I haven’t set that one up yet. I also don’t use nextcloud, so can’t comment on that.