I mean, the easy thing to do is revoke US-EU data transfers. The ECJ is definitely going to do it anyway, and it provides a lot of leverage. If you keep it gone for long enough, then the Mag7 are basically forced to store data in the EU, and respect the laws.

As a bonus, it would nuke the markets, causing the US administration to backpedal on whatever. (Obviously I'd prefer not to nuke the markets, but something needs to happen to push back against the US).

This would only happen in a world where the US has entirely abandoned Ukraine though (i.e. no intelligence sharing).