I think a reality check is what's needed. Google will always release first as that's where the initial code base stems from and the other OEM build the customisations and skins on top of that.
All the info about beta 4 has only come from tipster ice universe. Granted they normally get it right.
The thing with the beta is that it comes with no guarantees from Samsung and is purely opt in to try and help make the final version as good as it can be
The following is just my personal opinion but I feel Samsung have actually done a really great job with this beta. I have done the last few and this has been the first time I have really seen no game changing bugs that stop me using phone as daily driver.
The beta should be about submitting bugs and letting Samsung fix as quick as they can. The wait will make things better for all of us not moaning that's it's not released. The world has bigger issues