It’s a Lemmy thing, not just on jerboa. I just sort by “top day” to see the top posts from the past 24 hours. Once I’ve seen most of those, I switch to new all, which keeps a decent amount of new content coming through.
The platform is still young, so it’s a combo of a) not enough content yet and b) early sorting algorithms that paradoxically haven’t caught up with the influx of users yet.