To expound upon my point, consider that we currently believe that our own solar system is rotating around a supermassive black hole, and in fact all large galax

To expound upon my point, consider that we currently believe that our own solar system is rotating around a supermassive black hole, and in fact all large galaxies are believed to contain supermassive black holes at their center. Our solar system is subject to gravitational time dilation from those black holes, and so while our world lines may never meet with a galaxy far away with its own supermassive black hole, objective time differences will absolutely be present.