You are totally right ! It was Signal Desktop that had that many dependencies ; just checked my local clone. I had been compiling Telegram and Element at around the same time, and got mixed up.
Thankfully, you were here.
I'll edit my original post, and profusely apologize to the fedi for such a blunder.
@Goutte from what I've heard, Telegram devs are more of a "reinvent the wheel" folks than "pull hundreds of dependencies" ones :)
Their end-to-end encryption implementation is usually criticized for that, for example.
@evacide