Betas are not a progression. Apple can and likely does introduce issues as we move through the summer as they attempt to isolate other issues.
That said, of course there will still be issues once iOS 16 is released. But for the most part, they are not serious issues.
I would consider regularly occurring hard system crashes to be a serious issue, and this has been going on for the entirety of the beta cycle with no indication that it is being fixed. Odds are that the same issue I am speaking of is still present in beta 8, just like it was in 7, and 6, and 5, and 4…