EU freezes/takes over all Apple assets in EU, users with Apple devices get the money in cash upon delivering their devices. If the money isn't enough for the refunds, a finance mechanism can be created that will be settle after the war.

The returned devices may be sold to 3rd party markets if Apple isn't cooperating.

EU freezes/takes over all Apple assets in EU

Most value/assets are in the US, I don't see how Apple in Europe would have enough interesting assets to refund. If 30% of the 450M inhabitants in Europe have an iPhone and the purchase price was 1000 Euro on average, that would be 135B Euro. I would be surprised if they have a fraction of that in Europe as assets.

If the money isn't enough for the refunds, a finance mechanism can be created that will be settle after the war.

There are huge assumptions in this, like the EU wins the war, the war doesn't end in a sort-of cold war, Apple cannot get away from liability because it was not their decision, etc.

The returned devices may be sold to 3rd party markets if Apple isn't cooperating.

Flooding a 3rd-party market with over 100M second hand iPhones would drive down the prices by an extreme amount.