Third Party Photon -> Phoenix/Elixir sockets

Hi! We have done a 2 vs 2 Multiplayer card game in Unity with Photon as Socketconnections. We now want to control sockets on our own and get rid of all 3:rd party solutions. We are busy now with Phoenix/Elixir and want to migrate our Clients (Unity) from Photon to Phoenix/elixir(based on erlang) sockets

Now:
We are now using Exitgames Photon PUN as socket communication (Gameplay and gamechat) and using our own "gameserver" backend, meaning we have room creation, gameplaydata, users and all data on own server communicating with JSON meaning we are using Photon and 140USD / month only to communicate between the clients. (Always 4 players / game and turnbased, it's a cardgame).

What we want:
We "simply" want to skip Photon and use our own socket connections. Backend is not a problem but would like to know if anyone have experience migrating from Photon to Elixir/Phoenix in Unity.

Lets start like this and see where it takes us. Thanks!