gravity has to/is clearly works near instantly through the galaxy, otherwise it would fall apart.
Recent reception of gravitation waves simultaneously to light signals from a distant galaxy's dramatic dwarf stars collapsing one into another prove that wrong.
And quantum entanglement cannot be used to send information.
By definition, quantum entanglement IS information exchange in zero time regardless of distance. Changing the state of 'A' instantly changes the state of 'B', and any binary state system can be used for information exchange.
On gravity waves:
https://www.youtube.com/watch?v=SFJjrD5pq_IIf you really are interested, you should check out alternate explanations as well.
Standard physics explanation on gravity is a logical fallacy resulting from circular argument:
Mass of particles generates a gravity field in the 3d spatial space (whatever that is, it is undefined in material terms), and particles have mass because the gravity field of other particles "pulls" on them in the 3d spatial space.
It is a circular argument, a closed loophole of thought. Does not explain the origin of mass in matter (no, Higgs-bozons are a hoax, which assumes the 3d spatial space has magical abilities, non measurable ofc).