A single websocket can have 10 cost 1 subscriptions on it.
So you will run into that limit first
This sounds more like you want the regular/webhooks transport than the sockets transport for this use case.
And without auth you’d only be able to monitor
3 sockets
10 cost 1 topics per socket
2 topics (stream up/down)
(3*30 / 2)
so 15 channels…