This is true, we can travel only up to 8.2 billion light years (radius of the affectable universe/2) which is the largest completely causally connected region, in the sense that every point can observe and reach every other. 8.2 billion light years is the furthest distance that we could reach and then return from at the speed of light. And it is much smaller than the radius of the observable universe (46.4 billion light years)

The speed of light is an insurmountable barrier to us now and as far out as we can see, but we can’t really see that far out :p

> The speed of light (or compensated with very long travel time) is limiting

It's only limiting if you're trying to reach C when traversing the spacetime. But if you're bending spacetime instead, there's no such limitation!

Certainly there may be loopholes ;-) Anything I've seen with things like wormholes would require massive amounts of energy and/or exotic matter, as well as difficulties in things like stability and actually traversing with non-negligible mass. No free lunches!