inertia is a weird one. mostly it just means the state something is in when there are no forces acting on it. but general relatively theorized that an object in a gravitational field with no other forces acting on it is also in an inertial frame. it implies gravity isn't a force in the same way as electromagnetism - gravity bends space and time such that you're moving on a straight (inertial) line in free-fall even though you, for example, appear to be in a circular orbit.

so there's definitely room for our understanding of inertia to evolve, especially as we work out how to put gravity in the same framework as the other fundamental forces. I don't think it'll lead to faster than light travel but I'm speculating now on work thousands of brilliant people have failed to crack. just pointing out that there's a giant gap in our knowledge here where we have two very well verified theories that straight up disagree.