You are being tracked in multiple places, at the ISP level, at the geo level, cookie and account level, and I don't know where else.
Being able to reset your phone ID is insufficient given all the other ways you can be tracked.
With Apple, maybe they're the lesser of two evils, but there is still a lot of room they could improve if they really wanted.
The aforementioned iOS restrictions block you from being able to implement all the available privacy tools.
Being able to implement all those privacy controls is a double edged sword. There's a certain amount of security you get from not ever having root access. It depends on your threat model.
This is one of the paradoxes that exist with certain tracking protections that exist today. Eg. Enabling Do Not Track or fingerprint blocking could make you easier to track. Though these are becoming more ubiquitous, and therefore harder to use to track you, as browsers make them the default settings.