I don’t know about the iPhone 12, but on the iPhone 11 there’s a dual purpose antenna that connects directly to the motherboard that snaps into place was that properly reinstalled in your phone?

Aside from certain situations where you’re taking pictures and the use of the always on display, there’s no difference. The molar reasonable thing to do would’ve been replaced the battery on the 13 for $99 and then wait another year or two for an upgrade.

Is this the phone you were using constantly or is this a phone that you pulled out of a drawer some three years later to try to use? That iPhone requires a good battery in order to run, because the power isn’t fed directly to the motherboard, but it instead fed directly to the battery which powers the motherboard. You should actually stop trying to charge that phone since you might cause issues with that battery.

You’re thinking about it backwards there are certain items that will give you a gift card if you buy them primarily older stock items

Colorware offers very high-quality painting for your Apple products, including the AirPods. You should check them out and consider doing them in pink.