It's laughable to suggest that a 319 page document, produced by the government and it's lawyers, is "quite clear". If it was clear, there wouldn't be so much confusion about it.
The section you referenced: "If the internet is unavailable at takeoff, or if during the flight, the unmanned aircraft can no longer transmit through an internet connection to a Remote ID USS, the UAS would have to broadcast the message elements directly from the unmanned aircraft from takeoff to landing. "
doesn't explain what it means to "broadcast" the message. Does it require it to be in 2-way communication with a receiver before it is considered successfully "broadcast"? If not, as EndeavorOR says above, that's good. But if it does (as everyone else out there is saying), that's bad.
Page 10 says "The FAA proposes to address the identification issues associated with UAS by requiring the use of new services and technology to enable the remote identification of UAS. " But, it doesn't say what that is. It just says it isn't ADS-B. Hopefully it is some thing that is truly broadcast-only. Considering it is 319 pages, demonstrating they don't mind writing lots of stuff, they really need to make that clear. It wouldn't kill them to make the document 320 pages in order to clear up this very important question.
If you read the document you would already know the answers to all those questions. Whining about the length of the proposal is pure intellectual laziness. I suggest you read it before posting further. You only have another 309 pages to go if you already got to page 10.