The rate limits are why many of these sites poll at 5, 10, or 15 minute intervals, and often only top streamers as Helix has dramatically reduced accuracy after the first few pages if you’re requesting all streams.
Also it’s worth noting that site like TwitchTracker are somewhat BS on certain metrics, like their subscriber counts for channels can be off by +/- 80% is the worst case I’ve seen from partners I work with so I can compare their actual numbers to what TwitchTracker shows.
It’s also possible for some of these sites to have a higher rate limit, as it used to be possible to request a rate limit increase if there was sufficient justification. This is now no longer possible though so any new apps must work within the current rate limits.