And to add to this, a few of us at haproxy are part of the UDPA-WG (universal data plane API working group) with Envoy people to help figure how to define a uni

And to add to this, a few of us at haproxy are part of the UDPA-WG (universal data plane API working group) with Envoy people to help figure how to define a universal/portable data plane API which would work across multiple load balancers. This sounds like a tedious task but your concern definitely proves it's worth the effort.