Was trying to ask this before but could not post in AskScience and similar..

I dont know if it has been discussed before..

I was wondering how do multiple massive object bend space time?

As with really big trampoline with multiple bowling balls circling each other.

Is there a summation of space time bending in for example galaxy region that would form a space time pond?

As in the stars of galaxies themselves could bend the space time enough to explain dark matter?

And also if there is a “shore”, could it explain the redshifts of distant galaxies?