Thanks for the response! 
I do tried with Playfab, but since it has a lot of limits I was looking for another solution. Another reason was, that I don’t know how to create something like chat with Playfab 
So, I found Firebase that is used widely and there are even many tutorials about creating a chat for an Android app for example. So, with Firebase CloudSave, as I saw, it’s possible to establish a database too, I guess? I will consider Steam too, but I’m not a fan of that 
You mean this extension: Steamworks - Native Extension, not DefSteam?