Fahad Closed beta is already released for a couple of weeks. Open beta should be usable for a wider range of users and use cases so imo they should take the time they need to optimise the open beta version instead of giving lots of people buggy software with high power consumption.
I took part in Android 16 M3 Expressive Beta on Pixel and I it was nothing special, and the same holds true for NOS3.0 closed beta last year which I took part in too. So just be excited and keep on waiting. It will be released, no worries 😃