I'm currently looking into using Apache APISIX, seems really interesting - especially the part of writing custom plugins.
At Swisscom [1] we've created an APISIX [2] Plugin [3] to interact with Open Policy Agent (OPA) [4] to perform certain actions depending on the result of a policy evaluation.
An integration with Ory Keto [5] could allow us to have a centralized API Gateway with authentication and authorization termination (by using opa-keto [6]).