I was on beta 2 on my 17 Pro until this morning, when all internet connectivity stopped. Nothing via cellular or WiFi. The only thing I could do with cellular was make and receive calls, and who does that anymore? (kidding, but it's true that texting has replaced probably 50% of my non-business calls)
I do not know if beta 2 played a role in what happened. Just thought I'd note this experience.
The phone is working now. But none of the easy or moderately easy fixes worked, I had to use the nuclear option - wiped the phone and reinstalled the OS (which was the latest public release, 26.2.1). Happily, upon signing into my Apple ID, I got all of my contacts, my history of text messages and email, my calendar events, etc etc. Like you would expect. Unhappily, the phone doesn't see the iCloud backup I made yesterday (maybe because I was on 26.3 beta 2 when the iCloud backup was made), so, alas, I have to manually download & install all 3rd party apps.
Again, quite possibly not a 26.3 beta 2 problem. But could be, I really don't know.