I think the only time they remove FSD from resales is when they repurchase the cars to resell themselves and then strip the used ones of FSD/upgrades. With private-to-private, private-to-dealership or dealership-to-private ownership transfers, FSD stays with the car.
In most countries they also have "FSD transfer", which means that if you trade-in your current Tesla when purchasing a new one, your FSD "license" is transferred to the new car.
I think the only time they remove FSD from resales is when they repurchase the cars to resell themselves and then strip the used ones of FSD/upgrades. With private-to-private, private-to-dealership or dealership-to-private ownership transfers, FSD stays with the car.
In most countries they also have "FSD transfer", which means that if you trade-in your current Tesla when purchasing a new one, your FSD "license" is transferred to the new car.
As far as I recall, I think this article is still valid on this topic: https://www.findmyelectric.com/blog/does-full-self-driving-f...