Most users will not conclude from "sharing how nearby" people are, that someone could pinpoint exactly where they live by triangulating.
Unless Telegram does some extra steps to prevent exact locations (see other threads here), they should name it "share my location" instead of "show nearby users".
People nearby.
Quickly add people nearby who are also viewing this section and discover local group chats.
Please allow on location access to enable this feature.
"Allow in settings" (a button)
Then you see a system location access dialog. iOS allows to choose between (always, when in use, nope) and optionally to turn off "high precision" setting (not sure how much, but it covers entire city when off).
Then you may tap another button named "Make myself visible". I didn't, but a list of nearby users/groups was populated regardless.
Unless Telegram does some extra steps to prevent exact locations (see other threads here), they should name it "share my location" instead of "show nearby users".