Just two weeks after the latest iOS 16 release we now have Beta 3 (Build #: 20A5312g). Further review of what has changed will be coming soon so stay tuned. Also released macOS 13 beta 3, watchOS 9 beta 3, and tvOS 15 beta 3.
Public beta versions of the developer builds are usually issued shortly after the developer versions, but typically not after the initial few builds of the initial milestone betas. When they do, they can be acquired from the Apple Beta Software Program website.