Buying an iPhone for photography: Which should I get?

Hiya, I currently have an iPhone 6 and I am considering upgrading to something like iPhone 8 Plus or iPhone X. The absolute main priority for me is camera quality.

So far, I've got the iPhone 8 Plus and the iPhone X as my main two candidates to get. Would you say one is better than the other or that there is a better option than those for photography?

If anyone could help me, that would be greatly appreciated as I have quite some difficulty gathering information as to which I should get. Thank you.

P.S. I do not want to get anything above the iPhone X (Such as iPhone XR/iPhone XS Max/iPhone 11 etc) as they are currently very pricey for me.