But apple also cannot just stop selling or supporting their product in the UK either. So that card is dropped from both sides. As long as apple is beholden to a few million costumers and subscribers to their services in the UK; UK law is able to pressure them, fine them and restrict them because of those users.

We don't want it the other way around; companies placed outside the borders doing and selling whatever they want without a care. So we end up in a negotiation.

Apple choose to maliciously comply; subtly revealing the TCN, giving all UK users notices about what their government demanded of them to encourage public outrage, and push on the correct parts of the UK government that has their interest in mind.