New & Old iphone issues

1. I purchased a new iPhone 14pro.👍
2. The SIM card was taken out of my iPhone 11 and installed into new phone.
3. The content of the iPhone 11 was installed into the iPhone 14pro.👍
4. I was told that I can give the iPhone 11 to my wife, just move her SIM card from iPhone 8 into the iPhone 11.
5. I wasn’t told to do anything else.

Now my new phone and iPhone 11 are cloning each other.

I delete a text, email, app off one , it happens on the other.

I tried to change the Apple ID on the 11 and at the same time it was writing over the I’d on my new phone. Scary.

There are items I don’t want to lose on my new phone but need to remove from my old 11 that’s going to my wife.

Help.