While authelia is quite cool "infra-as-code" tool, since you have your entire configuration in yaml form, for those not willing to spend a few evenings configuring SSO, there is authentik [1] which features management UI.
Offers similar feature set, also self-hostable, but most importantly - simple to set-up. I've spent 8h on authelia deployment, where 30 minutes in authentik would be sufficient. But both are good options, pick what you prefer.