TikTok is not the problem. The problem is “I have nothing to hide” mindset. People don’t care about privacy because “ignorance is bliss”. Some people are just not aware about risks of giving up on privacy and other put continence over privacy. Until the general perception of privacy changes, apps like TikTok will thrive.
I use SMS and good old phone calls. You would be surprised how much people freak up when you call them. For work I use Slack, sometimes Teams. And on rare occasions, Messenger to talk to some family members.
edit Forgot about emails. I use it for more planned communications.