Charging iphone 12 with mac charger

It is okay. See the following from Charge your iPhone with an iPad or Mac notebook power adapter - Apple Support

You can use Apple USB power adapters for iPad and Mac notebooks to charge iPhone, iPod, Apple Watch, AirPods, and other Apple products.

and also see: Fast charge your iPhone - Apple Support

It is okay to use the charger for your MacBook to charge your phone. Your phone is not going to draw any more power than it needs to charge. If you have an adapter that gives off more wattage than the device needs, it's simply only going to use what it needs. It's like if you plug in whatever into the outlet, the outlet has way more available than the device that's plugged into it, however, the device only pulls what it needs.

It may charge faster than normal only because it's getting a higher wattage than the other chargers have which means that the other charger can't give as much as the phone would take so the phone gets the maximum that the charger could give. The MacBook charger has extra power so it can give the phone more power. You are fine using the charger that you are using to charge your phone.

Is better not to use a fast charger everyday, the one you are using is super fast and can heat up your battery.

Anyone else want to share their opinion, please do.

An iPhone will not draw more power from a power adapter than it is designed to use and it is safe to use even larger power adapters such as a 96W -- but they won't supply more power to the iPhone.