The contract YOU agreed to is pretty black and white. There's nothing "subjective" about it. It was fair enough for you to agree to it, so suck it up and either finish your obligation or pay up.
You admit you're looking for a loophole to break the contract that YOU agreed to.
Agreed. Hate to say it OP, but your options are fairly limited. You can buy it at the unsubsidized price, add a line, buy the iPhone on the secondary market, or stick with what you already have.