What's the worst damage a blown fuel pump can do?

[Mighty Shilling]

Yeah. When a fuel pump fails, the fuel flow stops, not becomes a deluge that somehow gets past the injectors and fouls everything.

Check the fuel pump relay and make sure it's getting power and you're getting fuel pressure...

And find a new shop...

And in regards to the fuel filter catching debris, you don't have a fuel filter. Your car has a non-return fuel system. at most it's equipped with a strainer on the fuel pump. The techs if diagnosing a fueling issue, may not have caught the heads ahead of time, unless there was a problem reported with the head. Generally if you say that there's an issue with your knee when you go to the doctor, do they check your wrist? probably not. Again, that's assuming the shop is correct in their diagnosis of a head issue (which I seriously doubt)