French here; my usage is mostly: WhatsApp for group conversations (circle of friends, family, setting up some event/holidays/whatever), SMS for one-on-one conversations. I am definitely not a heavy communicator, though: perhaps younger folks have different usage patterns.
As a reminder: most cell phone plans here include unlimited (free) SMS messages
Same here: WhatsApp for group discussions and whatever the default message app uses otherwise (SMSes or iMessage; does not matter much but we use iMessage features when we can). And Discord for the guild mates. And Facebook messenger for one group, but I don’t quite remember why we went down that route.
As a reminder: most cell phone plans here include unlimited (free) SMS messages