When I visit kbin.social, I see new posts regularly. On other servers posts stay on the frontpage for multiple days. This is also true if I switch their sorting to “hot”. So that is probably not the difference.
What is kbin.social doing differently?
I set my home to only show for subscribed community and sort it by new comment. Then I aggressively follow any comm/magazine than seems interesting. It make my feed comprised with both new and old-but-active posts/threads. Half of my first page feeds are constant, but there are new posts here and there. Enough for me not to get bored.