Yeah
Galaxies should be flying apart far more than they are if our understanding of gravity was correct.
To make the equations work they infer “dark matter” as a fudging coefficient.
But maybe there is no dark matter and our equations and understanding of gravity are wrong in some way.
or you can invent parallel universes with leaking gravity to make the equations work.
Frankly, I don’t think they are measuring the red shift/galactic regression correctly. I think the galaxies are not flying apart as quickly as they think, and thus their estimates of matter and gravitational constants are off.
But I’m not a physicist. I can’t even balance my checkbook without a calculator.