To be clear, what you're proposing isn't totally unscientific. There is some research around it but

While antimatter can be produced in very small amounts in particle accelerators, it is not naturally produced in significant quantities in the universe not even in blackhole.

We don't even know wheather it's even possible to capture or store antimatter in significant amounts for use as fuel.

Even If we did all that you still have to face that those challenges I have mentioned above.

Imo wormholes can make the difference I guess

Btw no disrespect just having some stupid opinion 😅 🌸