I don’t believe Einstein said there is no ether.
I believe he said the ether cannot be detected.
Actually, the Michelson-Morley experiment appeared to show there was no ether wind. But there is: It’s just much slower than Michelson and Morley thought it should be. They were looking for an ether wind caused by the earth’s motion in orbit, whereas the actual ether wind is only about 700 mph on the earth’s surface at their latitude. The earth’s gravitational field travels with the earth’s center—but it does not rotate with the earth.