Not to dissuade you if you choose that route, but if you have a new iPhone that is unlocked, you could consider getting an e-SIM from a European provider, and having the option of dual SIMs. You could turn off your American SIM if you didn't want to incur charges from people calling or texting you, but then turn it on when you need to use it. I have T-Mobile which provides cheap international roaming, so I kept that SIM on in dual mode while also having an e-SIM from Orange for phone and data in France, but I could have turned off the T-Mobile SIM and just used the Orange SIM at any time.

Thanks for this; I had forgotten about this capability.