I have to say, beta 2 on my S21 Ultra is so much better than beta 1. Animations are quick, the UI overall is quick, battery life seems to be improved, screen refresh rate issue seems to have been improved, my wallpaper is no longer blurred out. Gpay support would be nice but I understand having to wait for that as beta isn't certified OS.
I haven't encountering any additional bugs tbh. I haven't tried theming as I have a theme applied from the galaxy theme store that I love.
Google Pay will not work due to not being certified, possibly the next beta 4.0 version will fix this issue