Small Yacht Network Design Critique?

So in a previous thread (Max HD 1 Dome + Wifi as WAN? - #8 by hoeken), I was asking about how to build a system with that has 4G via a MAX HD 1 DOME, ability to do WIFI as WAN, have a local WIFI network, and also potentially be compatible with Starlink and/or VSAT (this is a stretch goal).

I went ahead and bought some gear and managed to get it all working, but I’d like to know if this is really the best way to do it before I start pulling wires in my boat. Here is my current network diagram:

The Balance 20 is on 192.168.50.1
The Device Connector on 192.168.51.1 and setup to just do WIFI as WAN
The MAX HD Dome 1 is on 192.168.52.1 and setup to use the sim injector.

From a hardware point of view - is this the best way to go about this? I tried using the SOHO router, but the WIFI as WAN wasn’t working well, and it seems it can’t do both WIFI as WAN and AP mode on both 2.4ghz and 5ghz at the same time. It also doesn’t have an extra WAN port for when/if I ever get a Starlink dish to play with.

It also seems wasteful to have 4 power connectors, at 48v, 24v, and 12v, especially when the AP and the device connector support POE and the sim injector provides POE. It would be really great to have something like the Balance 20 that supports POE and has SIM support, but no radios. Am I missing a product in the lineup?

From a software point of view, is having them each on their own network like that the best way to do it? I understand the very basics of networking, but am definitely not an expert so be gentle. I read something about vlans on some other threads, but it went over my head. Any suggested reading to learn more about that?

If anyone is curious, I measured the total draw of the system at around 28-30w, and that was using all 4 of the supplied AC adaptors. Not an ideal setup, but definitely makes this do-able on a sailboat with big enough batteries.

This site has helped me tremendously

https://routersecurity.org/vlan.php

The Surf SOHO does have USB WAN as well provided you use a compatible USB Ethernet adapter.

Peplink has tested the following:

Post also shows how to enable the feature.

Thanks, I will check that out.