Babylon.js + ( N nodejs servers + M NullEngines )

I am trying to make a real-time moba (multiplayer diabloid). All the time experimenting with Babylon.js + Golang, I came across the problem of synchronicity, wrote my own collisions and movements up stairs on the server side, where there is no Babylon functionality. In general, I have a feeling that I am doing something wrong, and I don’t know something.
All this was done to avoid single threaded slow js + nodejs. I read somewhere that there are problems on one nodejs server 25 players.
I would like an arena with a capacity of 300 players. And there can be many such arenas (I would like to inexpensively scale the project in case of success: ~) ).

Now I am thinking about a new architecture and I need help.
Can I divide the arena into zones (let’s say 6 pieces of 50 players) and keep 6 running nullengines for each?
Can one Nodejs server handle this load?
Maybe I should have several nodejs servers (with different ports), each keeping its own piece of the arena? Or it’s wrong, not optimal, expensive, etc.?..

I think this could work as there were other people doing it (You should look for multiplayer in this forum)