How to hide the fact that I'm Qubes OS from Telegram

[barto]

@Qubie

I suspect this clock synchronization is going through clearnet. You can almost take that as a fact. So the question is: what does it tell to ISP and does it leak to ISP the fact that you’re using Qubes OS?

Your suspicions are correct (at least in the default install). But - big BUT - it does not leak the fact that you use Qubes, because it is a plain default Fedora clocksync setup. See Dom0 Clock Time Server .
At most, it tells your ISP that you run Fedora.

P.S To the angry moderator(s): I consider that this answer is not completely off-topic, and contains a link that furthers the discussion of OS fingerprinting, which is in the same direction as the topic of this thread.