I think for most performers, it's more hours for about the same or less money. Lots of experienced high earners seem to return just for contest weeks, and blow it out of the water! It's really impressive to watch some of them hustle during contests, I really admire them. Also during these times, it feels like the clientele shifts a bit because they are seeing lots of deals for low low prices, as many online performers are trying to get every last $ for their contest rank.
If you are already among the top earners, you may see this as a negative to a lesser extent than those who are already struggling to make what they need. I think contest periods make the extremes of earnings skew even further apart while they are going on (like all platform contests?). So I would go into it with the intent to log as many hours as I reasonably can, with the expectation that I either have to hustle a bit harder or accept a slightly reduced hourly rate. Lots of variation in prize amounts/distribution between all the different contests, but like many contests, the prize money isn't the biggest prize. It's the exposure and earnings you had to get there that really matter.
My favorites are the bonus periods, where we make an extra % over the usual cut. That feels so nice.
I am not sure how to answer whether or not it is hard to win #1, or top 10, of course you know it's work to be in the top so I will try to answer just about my experiences with what ranks I have seen. Top 100 is what I know is achievable for me because I have seen myself there, though I usually won't put hours in over what I normally work and more likely end up in 200-300s. I typically don't put a ton of hours in on live cam. I have never dedicated the time and effort to get stay in the higher ranks. I'm the kind of person who could maybe do that once, but then take two weeks off after to recover, so it's not realistically a great business model for me.