Netherlands here. 80 contacts on my phone. 20 on Signal, of which 10 are quite normal people. Almost all 80 are on Whatsapp. No idea about Telegram.
I only use Signal. Most of my contacts are on Signal (meaning people from work or close friends/family). I would say ballpark 85%+. My shrink and MD are on Signal. I'm lucky enough to work for an organisation that promote and emphasis privacy and security. I'm also quite a good evangelist to my family and few friends ;-)
Once I step out of that circle/bubble of people, I realize how peculiar my situation is, mind you. I have 2 teenagers and sometimes I have to communicate with "regular" people. EDIT : in that case, I use regular email, SMS or phone calls. WhatsApp is widely used in Belgium, as is Messenger. My wife tried to remove WhatsApp at some point, but that made her social life too difficult.
I am assuming US or Germany.
I can't remember which thing it was exactly but there was a huge privacy scare in the US at some point which got people to switch in droves to Signal. Maybe the WhatsApp T&C change?
German's have always been more privacy-aware (hence they have a much bigger cash payment culture than almost anywhere else in North-West Europe) and it seems like a steady trickle is switching over.
But for example here in The Netherlands, I'd say 99% of people is on WhatsApp, 10% is on Telegram, and 0.1% is on privacy-focussed messaging services.