Auth is a pretty classic case where it’s not hard to make your own account create/login form but it’s really hard to make a good one that does all the “right things”.
I have been building https://github.com/openrundev/openrun to try and solve internal tooling deployment challenges. OpenRun provides a declarative deployment platform which supports RBAC access controls and auditing. OpenRun integrates with OIDC and SAML, giving your code based apps authn/authz features like low-code platforms.
The advantage of third-party tools is that it's hard to get new features in there, so they retain their simplicity. You don't get some rando C-Level or IT guy demanding new auth features to make it messy.