My understanding is that maximum speed is defined when going through space so light speed is maximum speed while going through space.

But I think theoretically we can defined travel through spacetime (or by transforming space itself) or something similar where a distance can seem to be travelled at higher speed than light is measured as space. I am thinking about this as I heard that when thinking that our Universe expands so each two galaxies lets say depart from each other will eventually speed up “faster than light” in the sense that the space itself expands.

Or I can be very wrong so please correct me.