I downloaded the latest beta, and it would crash on the blue Logos splash screen when starting. So I deleted it, rebooted the phone, and did a clean install. It's still crashing.
It is a iPhone SE (2020) with iOS 14.7.1
Same problem on my iPad Air 2 (14.7.1).
Same happening in my iPad Pro 10.5”. I have also tried resetting.
Thanks, and sorry about that. We should have a fix pushed out before the end of the day.
You should be able to install an older build from the TestFlight app as a temporary workaround if you need. Open TestFlight -> Logos -> Previous Builds.