Go broad and achieve nothing. EU has all of the AI tech it had 5 years ago, and has the same tech allowed to use as the US.
What defines a model? What defines ownership of a process? If I make a wrapper to a remote VM that builds and executed a prompt, am I accountable?
When I worked at a company in the EU, it was enough to apply a reversible linear transform to the data for it to be considered GDPR safe-according according to legal definition as long as the transform details were stored separately.
Yes. You are accountable. Quite obviously, I might add. Why would no one or anyone else be accountable?
Hell, you can slip and fall and hold the cleaning company accountable. (This might be a US thing. Likely because that fall might cost a lot in medical expenses, and your insurance will do whatever it takes to pass the liability.)