What's the best camera around 1K that can do 120fps?

I am searching for a good used or new camera that can handle 120fps for that smooth slo mo cinematic footage look. I vlog and create fitness videos so I think this will only add to the overall value proposition of my channel.

Question #2 - is there a 1K or so 120fps camera that has interchangeable lenses that I need to be looking at?

Thanks! This is my first day here so I am trying to see how things work