Telegram OpSec

–General Settings
Never use real name.
Never use real display pictures.
Leave username blank; having a username makes you easier to identify and find.
Nothing revealing in your bio.

–Privacy Settings
Phone number -> Nobody
Last Seen & Online -> Nobody
Profile Photo -> Everybody (you’ll look suss without it)
Forwarded Messages -> Nobody
Calls -> Nobody
Add to Groups -> Contacts

Set passcode.
Set two factor authentication password.

–Additional Phone
Who can see it -> Nobody
Who can find me via it -> Contacts (not the best but it’s the best telegram will allow)

–Additional Call
Who can call -> Nobody
Peer to Peer -> Nobody