Thanks, I only have a loose grasp of how the physics work, but what I do know is that there are smart people who are paid to worry this stuff out.
I do wonder what the time difference is between the extremes of the livable band of the galaxy.
Did you know that relativity is "only a theory", but the GPS satellites in orbit had to have it calculated into their clocks so they would function properly? Several years ago one of the government's atomic clocks was moved from the ground floor to the second floor and had to be recalibrated to account for the gravity difference. Crazy stuff.
I think general relativity is both right and wrong, or incomplete. We had to add dark matter and dark energy to make it match what we observe beyond our galaxy. Infinite density of a singularity is problematic. Quantum gravity is a bugaboo.
But it also makes a number of predictions that we have been able to test and confirm.