The idea is that you would subscribe to hashtags to see what people talk about. Or you can go in "Local"/"Federated" and you see what people talk about in your instance or within their network. But it's all chronological, there's indeed no algo to tell you who to follow (Twitter used to be like that, you'd show up to an empty feed basically)

Not sure why it is that slow, might be the server? Mine is quite fast and followed the WWDC keynote in real time with sometimes dozens of toots a minute