Star Trek only works because they have warp propulsion and that unfortunately is likely to remain fiction unless we discover some fundamentally new aspect about how physics works.
Even as fiction, Star Trek is a bit ridiculous. I guess I've never paid attention to whether they've left the galaxy, still, within the galaxy, you have to exceed the speed of light by huge factors to get around. It's 52,000 light years across. I know on Star Gate, they travel between galaxies, which is truly mind boggling distances, millions of light years.
How did they put it in Hitchhiker's Guide? '"Space," [the Hitchhiker's Guide] says, "is big. Really big. You just won't believe how vastly hugely mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space.'
Something I just learned, is that there are galaxies so close, they appear larger than the moon!
https://apod.nasa.gov/apod/ap061228.html