Well, your first point is irrelevant since with Telegram you also need an account, and more so, here that’s for any file size.
As for the second point, I understand you concern.
As for the fact that Telegram “is a data-mining app”, Tom Swift Sr., I suggest you to inform you more by reading their faq, I was skeptic firt too but it’s not as awful as I though, the true thing that we need to be careful of is the bots that are integrate by channel administrators as they can give a wrong impression of trust (I invite to read this) and we not forcibly know their purposes (so it’s a matter of trust).