Hi davey!!!
I did 250-Superstock from 2017 to 2021. At start, there were 10-15 entries for each race, by end, just 2-4, really sad. Now it's gone completely!
However, you can still run 250 one class up, although 300-WSS is really tough with MotoAm spec bikes and racers. Look up Rocco Landers from couple years ago, he kicked some serious ass in AFM before moving onto MotoAm.
If you're decently fast on 250, you can actually be competitive in 300 class. Here's fastest guy in 250 class, Jordan Edginton. Within couple laps, he catches and passes entire 300 field!!!
Link to original page on YouTube.