If you have an Android computer (aka smartphone) and you have the Facebook app and you delete it, it deletes one out of 4 apps that are installed. You will still get tracked and spy continues as usual. You need to connect the "smartphone" to the computer and remove all other 3 spy apps. This is for the apps topic. The app's data means absolutely nothing. All data that Facebook receives is never ever never deleted. Nor if you request it. Ever. But every app uninstall should also remove all the data. I don't know it if does.

I tried that, and it still has access to account username on reinstall.

Is Ad Tracking enabled for Meta app(s)? https://www.cnet.com/tech/services-and-software/dont-want-yo...

Does the iPhone have an IPv6 address that is unchanged between the first app install and 2nd app install?