Recently had similar problems. Main problem turned out to be fuel pressure regulator. It sits at front end of engine fuel rail, and a rubber hose goes from it to intake manifold. Simplest thing is if you can borrow healthy FPR from similar car and swap. Test also if fuel pressure remains in system after brief engine run. If not, FPR probably leaky. Low fuel pressure will give lean mixture, and thus knocking tendency, during strong acceleration, but you won´t hear the knocking but instead experience that your engine control system cuts back on ignition timing, leading to the power drop you experience.

Try this, simple to fix if this is the problem.

Gustaf