Space and time are defined in physics by standard rulers and atomic clocks. If objects try to occupy the same space at the same time they collide and the standard model claims that matter only moves when other matter hits it. But gravity ignores this rule because it lets the sun hold the earth in orbit even though they are millions of miles apart with nothing between them but space.
Einstein’s answer was that matter can change space and time. Special relativity lets moving matter alter its own time and space and general relativity lets large objects change time and space for objects around them. The equations work but they don’t say how matter changes time and space and Einstein made no suggestions as to how matter changes space and time.
The standard model doesn’t help because space and time aren’t particles and it has no particle that can alter space or time. Can a painting make the frame it presents within larger or smaller? Can a movie make the projector running it go faster? Current physics has no answer to the question how does mere matter change the time and space it exists within?