>For instance I have an iPhone model, so why would screen resolution help increase identifying bits coupled with the user agent? Everyone with my phone version and OS version will have the exact same values.
The user agent for mobile safari doesn't identify the iphone model, only that it's an iphone[1]. Knowing the precise model definitely helps to fingerprint more.
[1] random search: Mozilla/5.0 (iPhone; CPU iPhone OS 12_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.0 Mobile/15E148 Safari/604.1
The user agent for mobile safari doesn't identify the iphone model, only that it's an iphone[1]. Knowing the precise model definitely helps to fingerprint more.
[1] random search: Mozilla/5.0 (iPhone; CPU iPhone OS 12_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.0 Mobile/15E148 Safari/604.1