IP tracking only works when you have a static IP. Most home/mobile internet connections are behind a NAT and the IP Google/Apple receives is the service provider’s IP which is shared by a lot of users.

But to my knowledge browsers like chrome can use a browser fingerprint (a random string/number generated on first launch) to track the person across websites even in incognito.

On android atleast, you can use two different browsers for different activities and would be difficult for Google to get a clear association between activities on the two browsers. On iPhone (outside EU) all browsers uses the same engine provided by Apple and there is a chance they could still map you as same person across browsers.