How do I get past the SIM required without having a SIM card for iPhone?

You should be able to activate without a SIM card by connecting to a computer with iTunes.

So unless this is an iPhone 14, the phone has a physical SIM slot. Any SIM card would do. Even an old SIM card that's lying around inactive. A SIM card from someone else's phone. Once it's set up the SIM card can be returned to whichever phone it came from

I would absolutely never use someone else’s SIM card to activate a phone.  One of my own old inactive SIM cards, yes, but someone else’s SIM, no.  Too many chances of unintended consequences.