As far as I know recent iPhones all have parts pairing, so you can’t swap parts between phones unless Apple authorises it. Absolutely sucks ass for repairability, but it’s supposed to help in the context of stolen phones.
I guess thieves found a way to circumvent it, otherwise it wouldn’t make sense
I’ve repaired and tinkered with many phones and computers, I thought I’d be able to change the battery in my third gen iPod nano… But I completely messed it up because of the soldering. It ain’t easy :(