Possible to change logic board bcz of activation lock?

Sadly Apple's policy of parts pairing has only gotten worse over time, to the point where the iPhone 14 is one of the worst phones on the market in terms of repairability. And that's not because of the mechanical design; they originally got a score of 7 out of 10 for repairability, but after examination of the parts pairing done to the phone, iFixit dropped their score down to a 4 for the simple fact that many parts will no longer work after being replaced. Here's the article I'm referring to.

We Are Retroactively Dropping the iPhone’s Repairability Score

What that means for you is that swapping out the motherboard means that a large number of functions on the phone will simply stop working. Face ID will be disabled, True Tone will no longer function, you won't be able to see your battery health, your selfie camera can't take pictures, wireless charging won't work and your taptic engine may or may not still vibrate. Here's a chart listing all of the parts pairing Apple has done to the various models of its phone.

So basically you would have to buy a replacement motherboard and all of its paired parts if you want everything to work. Unfortunately, that means you now need most of the interior components of the phone, so there's no point in swapping a motherboard when you need everything else as well. Apple has made sure that swapping a motherboard is no longer a viable solution for getting around an iCloud lock.

Sorry I don't have better news for you, but I'm afraid you're in a bad situation. You can't get the lock removed, and you can't use the phone for parts, so it's basically an expensive paperweight now.