Thanks for providing all the details. I also did some reading for you. I have always purchased SIM-Free iPhones and paid in Full. That is my experience. I then used the iPhone with any carrier that I chose.
You are right about the multiple types of payment plans and some are associated with AT&T or Verizon. There is one that involves Citizens Bank and one plan that involves the Apple Card. All are 24 Months and interest free.
- The AT&T and Verizon plans requires the iPhone to be locked to them. They do provide a small discount by locking your iPhone with them (along with the service) for two years. Of course, these two will get their money back form the service bill side over two years.
- The Citizens Bank financed plan requires the buyer to activate the iPhone with one of these four carriers. AT&T, Verizon, Sprint or T-Mobile. As soon as you activate your iPhone with one of those 4 then it will be locked to the carrier that activated the iPhone.
- Then there is purchase with the Apple Card. If you have the Apple Card then you can finance your iPhone on it for 24 months and you can purchase a SIM-Free iPhone using this method. The Sim-Free iPhone will remain unlocked for use with any carrier at any time.
- Finally the pay up front option. Pay in Full at once and the benefits are the same as point 3 above.
I believe, that Option 3 or 4 works best for you because you wanted to use Consumer Cellular. I checked out Consumer Cellular's website and noted that the iPhone 12 (all models) will work on their network. I think that a SIM-Free iPhone + Consumer Cellular saves you the most money.
Good Luck in decision making. If you can, or want to, then please let me know how you decided to go further. Thanks.
Axel F.