Among many of the features I’ve just now discovered because of my time spent digging for this Post, Telegram’s acceptance/support (as far as I’ve been able to determine testing only in a few scenarios) of full, uncompressed media file input from the sharesheet feels to me like the most surprising.
I maintain that Telegram for iOS’ integration with the YouTube app's ancient, bespoke Share Sheet is the fastest way to just get the share link and get the fuck out the goddamned place.