A chat bot will be disconnected from Twitch Chat if the chat bot can’t keep up and the “message queue to send to the bot” gets too long.
So a small bot will manage fine on a single thread/connection, but you will likely need to add more connections over time if you need to spin out to send/recieve to a number of channels, but thats likely need the triple figure channel depending on a number of factors.
And how you spin out depends on what your bot does and how well it can keep up.
So grow till you have problems and then adjust from there to match your usage.