Even beings with tens of thousands of years lifetimes would find travel at sub-light speed to be booooring to go through just to come here. If they’re coming, there must be another trick.
Thought about that same thing myself. I really don't think the speed of light is breakable. At the speed of light time stops and distance goes to 0 (from the reference frame of the object traveling at light speed). Basically the object would wink out of our four dimensional reference frame (3 spatial/1 temporal) and into it's two dimensional reference frame ....no distance, no time like maybe a photon). With no time or distance there isn't going to be any movement within the object therefore no way to decelerate the object, other than smashing into something.
Maybe it won't be boooring for a species one million years advanced. Standby for travel, boot up on arrival, standby on the way home, boot up on arrival home and finally download to catch up on the last twenty thousand years. You've got to figure one million years advanced their brains will be heavily computer aided. We are damn near at that point ourselves.