If you bot is operating in only one channel.
And that bot is a moderator in the channel.
Then in theory, it’ll be really difficult to hit the rate limit.
However:
Then your bot uses one point to JOIN
And that’s it.
If you bot sends no messages, then you use no rate limit points. And thus you can’t hit a rate limit, since you’ll just use the single point at connect.
You can even use an anonymous login to chat since you don’t intend to send any messages.
Just remember to PONG in response to Twitch’s PING to keep the connection alive (which tmi.js probably handles for you. Assuming when you say TMI you mean TMI.JS the JS library and not TMI which is the name of chat itself.