New Product wanted. Does not exist anywhere. Zwave / Zigbee repeater across home network

Sounds like the Z-NET I mentioned above, which just a network-accessible Z-Wave controller (creating its own network), not a Z-Wave repeater that works over a network interface.

There are other ways to get what you want. I use Home Assistant and Z-Way. I’m using Z-Wave without using a mesh network. There are drawbacks to a mesh and you can easily get a congested network with a lot of devices. I have one “core” Z-Way instance that communicates to Home Assistant and also to the remote Z-Way nodes that have the Z-Wave devices. The “core” Z-Way instance knows of every Z-Wave node. I can either do automations in Home Assistant or in Z-Way. The remote Z-Way nodes are just a Raspbery Pi CM4 using Ethernet. You could do this wirelessly as well.

If you have a mesh network and need to get to the farthest Z-Wave device, it will take longer than my setup since 1Gbps Ethernet is always going to have less serialization latency than Z-Wave will ever see.

You do manage the Z-Wave devices in Z-Way though but they appears in Home Assistant using the integration. For reference, they are adding Zigbee support to Z-Way. They are going to start selling a mPCIe card that has both Zigbee and Z-Wave support on it.

Z-Wave and Zigbee mPCIe adapter can be used together with Z-Way software or any other third party software that uses Z-Wave Serial API and Zigbee NCP Serial API. There are firmwares for static controller (for Z-Way and most of third party software) or bridge (for Z/IP).

I believe in HACS there is an integration that allows you to integrate multiple Home Assistant installations.

I would not want to traverse long distances with either Z-Wave or Zigbee and have one big combined network.