Another solution is to use NAT on the router. NAT all traffic from the client network 11.0/24 to the routers IP on the server network 10.0/24.

That way when the server sees the ICMP echoes on its 10.102 network it will look like it came from the router and send the reply back together router instead out its other interface.

If you’re looking for a more mature networking setup, I would definitely recommend splitting up your router, switch and AP duties into separate devices. It gives you the most flexibility for when you want to tinker or change things.

For a main router setup, I would recommend OpnSense. It’s has a cloud backup feature which allows you to automatically backup the configuration to a Google Drive xml file whenever it is changed.

The XML config file stores all your leases so you don’t have to worry about reassigning DHCP reservations. If you load the config onto a new system, like for an upgrade or if the router hardware fails, usually you just have to change the interface mappings and you’re good to go.

As far as APs/switches, I would recommend Unifi or Mikrotik. Unifi has a fancy dashboard you can use to adopt new equipment and restore/change configs from, but I find Mikrotik easier and simpler to backup and I like that i dont have to host a controller to make config changes.

Is the NIC built into the motherboard or an add on pcie card?

You could check the journal to see if the logs tell you anything.

Once you change your DNS server in your router, make sure to renew your clients DHCP lease. It may still be using the stale DNS server. On windows verify its using the new DNS server with: ipconfig /all

For future reading this “multiplexing” is called SNI inspection/routing and it can only be used when TLS/SSL is in use.

Have you checked that your physical devices aernt blocking incoming ping requests? Like windows firewall?

If you are into RPGs Foundry VTT is a great replacement for roll 20 or any of the other virtual tabletops.