with the data only plan, you don’t.
but i’m finding that imessage and all the half-dozen chat apps everyone uses (whatsapp, telegram, signal, twitter dms, etc…) cover all the bases for me.
facetime is my phone replacement for calls, and in my situation it’s perfect… though i do understand that some may disagree.
silent link does also offer a plan that allows you to have a real phone number and accept inbound sms & voice calls, but i didn’t think that was necessary.