Authorize Curl requests to microservices

Question

I have microservices architecture and want to add authorization and authentication (JWT/Oauth2) for curl/Postman requests.
Microservices running inside docker containers.
I don't want to modify existing services and prefer such schema:

• I tried to use oauth2-proxy with keycloak, but it offers sign in by web interface.
• This SO question (Microservice Authentication strategy) didn't help me.
• Diged in Envoy External Authorization envoy front-proxy example. But it need to add envoy instance for each microservice and have simple auth check.

Questions:

• Is there another ready-to-use solution?
• Can you suggest direction or technology to continue research?
• Or it will be easer to write own auth service, working in pair with reverse-proxy and Auth Provider (Keycloak)

Answer 1

Input data: oauth2-proxy, keycloak, nginx, one API - service - working together in docker containers. Authentication by OAuth2.

Solution: I simulated web logging in by python according to this video Python Requests login and persistent sessions tutorial
It is more simple than using python requests-oauthlib library or Postman, curl requests.