Did you consider using commercial nginx? If so, what made you decide against it?
Things that may've help:
-- Configuration definition (e.g. protobufs.)
-- More focus on observability: error metrics (instead of logs), tracing, etc.
-- gRPC control plane.
-- C++ module development SDK.
-- (ideally) bazel.
Some dataplane features like gRPC JSON transcoding, gRPC-Web, and http/2 to backends.