iPhone 12 Pro vs iPhone 12 Pro Max

Hi,

I'm planning to upgrade my iPhone X and get the 12 Pro or Pro Max. I'm still on the fence as the Pro Max is really big, but has potentially better camera features which might be worth it. The main differences that stop me from buying the 12 Pro right now are the bigger sensor in Pro Max (so according to Apple 87% better pictures in low light). the lens-shift optical stabilization and the slightly longer battery life on the Pro Max. But on the other hand it has 6.7" display which is way more than the 12 Pro's 6.1" and certainly more than my iPhone X's 5.8". Do you have any advice?

Also in case I get the 12 Pro on installments is there a way to change my mind within a month and pay the difference and switch it with Pro Max or contracts are final and there's no period where you can change your mind? I'd expect there will be reviews of the Pro Max within a month so I can be more certain if those potential improvements of the Pro Max are reflecting in practice or they are mostly theoretical and/or not worth the price.

Thanks,

Dejan