That would not be the smart thing to do. Sanctions would hurt EU economy more.

There are a lot better responses: reduce copyright length, to let's say... 50 years? Make everything after 1976 public domain. EU economy could even get a boost from that.

Or, if EU wanted to keep this limited to justice, denounce extradition treaties for all but most serious crimes (expecially not allowing any future Assange to be extradited), repeal laws that forbid bypassing DRM protections and reverse engineering.

We have a proxy war with Russia and need US oil/gas. There is zero strength or political will to oppose US now, EU strategy seems to be just wait it out.

When your opponent is making a mistake - don't interrupt them!

Why is it up to other countries to solve your domestic issues?