Hi 

is it possible for to establish site-to-site VPN or client-to-site if my gateway VPN server not using a public IP or its only NAT from my router (having Public IP)? Does it establish VPN tunnel? Im curious about the auto ipsec setting

Just like a traditional SDWAN, my remote VPN box can able to build VPN tunnels. It is able to know via orchestrator management.

At the moment, i only have one TL-R605. But i plan to buy one more if this works.