What internet speed is required for online gameplay?

I'm in a hurry to disappoint everyone, the game runs perfectly fine.
The speed is up to 5kb/s in duels, and if the internet connection has no delays, everything is great.
You can play on maps up to a large size, i.e., small and medium-sized maps. Large maps are also playable, but there will be lag, so you can only play 1v1 and not be the server.