Setting up new phone

If I recently got a iPhone 14 pro after having a 7plus for 4 yrs but my phone number in my new phone is actually just my iCloud address and I have no cellular data. I looked and that means I have to change my sim in my old phone to a eSIM but I can only do that if both are on ios 16 or newer and a 7plus can’t go to ios 16 so what I should do next? Also once I switch my sim to a eSIM will it completely shut down my old phone?