I'm afraid so. Ion drives are ok for tooling around the solar system at about a hundred kilometers/second. But 10% the speed of light is 30,000 km/sec. That's quite a difference. An ion drive might be powered by a fission reactor with a few hundred pounds of plutonium aboard, and it still needs a propellant mass to jettison to provide thrust. In fusion, like chemical drives, the fuel doubles as propellant mass. A fusion rocket would have 4 tons of fuel for every ton of rocket.

Hopefully, we may find other gofast drives in the future, maybe even FTL. But right now, the only thing nature has that we might be able to adapt to our purposes is fusion, and in the fusion reactions I know, much less than 1% of the fuel is actually converted to energy, and that is further whittled down by the other factors I mention. In fact, even the 1% figure I quote in my essay may be wildly optimistic .

The guideline I like to use in my fiction is that anything that nature can do, we will evenutually be able to duplicate. But anything else is just guesswork and wishful thinking.

The only way we could get up to relativistic speeds
(over 100,000 km/sec) is with 50%-100% energy conversion (an anti-matter drive). This is theoretically possible, but nature doesn't seem to use it for anything, so I am not too optimistic.

As for FTL, we don't even know where to start. It's one step short of magic.