> Care to explain further why there should be zero regulations on the UX of monopoly applications used by ~15%+ of world population?

Because there isn't a monopoly on chat apps. What you're asking for sounds like rules for the sake of more rules. I can think of more than half a dozen chat apps offhand: Signal Messenger, Whatsapp iMessage, all manner of IRC clients, Slack, Teams, stock SMS, Discord, Matrix/Element, Telegram, Session, and so on and so on.

We're not talking web search here, the market for chats is diverse and competitive. You got walled gardens, open source, and everything in between with a bunch of different UI's.