You don’t know what lockdown is do you? I’ve had my phone in lockdown for a year. I can’t: collaborate on notes, and it does not automatically open links in chat. Other than that my experience is identical to non lockdown.
I can send my friends a PDF of a restaurant's menu over iMessage. I think that wouldn't work for you?
You lose a lot: https://support.apple.com/en-us/105120