Hello.
Thanks for the thorough description of your setup, there is not much to ask.
1. The way you've described you want to use ERS contradicts the main idea of ERS: the radio should be in the same subnet as the server software.
2. Please check your 10.10.10.0/24 with Wireshark, does it detect the data?
3. Manual input of the IP address will be implemented in the ESDR3 by the end of 2021.
4. I cannot say the same about ERS, it's far from our priority at the moment, TX mode has a way higher value. Maybe at some point next year we'll look into IP routing.
On top of that, it's not a trivial task, as I said ERS wasn't designed for such operation, server software connects to the Cloud as a client, the same applies for ESDR3 client instance it also connects to the Cloud as a client. So, as a result, you don't have to open certain ports for them, they operate as outgoing connections, not incoming. Server-Cloud-Client exchange all required info like IP, UUID, etc. automatically, there is no need to manually enter anything.