I've been grinding blind fight for a while now and it seemed fine for the longest time but no one has entered my league except 2 people in the last 3 days. Did people suddenly just stop playing or is it down?

Hi, I see there are currently 8 players in your league so looks like whatever issue there was has been resolved.
It will sometimes take more time to fill higher tier leagues due to how system is designed, which may occasionally lead to situations where you have to sit through several league resets.

Yeah I spotted those this morning, thanks for the insight!