What details are you assuming Telegram are sitting on, besides the data law enforcement already collected?
Durov got arrested for insufficient moderation of public channels, so my guess is that law enforcement would be able to get exactly the same data as Telegram themselves sit on.
But it's hard to get a full picture without it going to public courts, for now we can only go on what's being reported.
Message contents (vast majority of TG chats are not E2EE) and additional metadata seem pretty desirable?
I believe it's as incorrect as arguing the United States wants to ban or own Tik Tok because China has access to Americans private data.
Whether the US has sincere reasons for proposing a ban is a station that has by long been passed. If your point is that "social" media is mainly a tool in the hands of tech elites, whose main business model is social upheaval and where foreign influence is up for the highest bidder (troll farms), then yes, I agree that we should have a broader discussion of what we as democratic societies expect from those profiting from information chaos, distrust in societal institutions, outrage, and advertisement clicks.
Parasitic tech elites and their tools of influence in the information sphere have nothing to do with free speech -- in fact they kill a fair debate among equal citizens in a democratic society.
If Telegram did actually prioritize private and secure communication, they would indeed be just a data pipe and nothing could be shared with law enforcement.