:D Truly?
So does that mean you won't use any cloud service (e.g. AWS, GCP, Azure) ? And no Authentication services (e.g. Auth0, AWS Cognito, Firebase)? ...
An authorization proxy is quite the same, and I would argue that for some teams is much safer to use than building your own AuthZ. Broken access control is the top OWASP risk for a reason (i.e: implementation complexity)
source: https://owasp.org/Top10/A01_2021-Broken_Access_Control/