I'd like to see a galactic computer simulation with GR. It may be more complicated, and it may take a little longer to run, but it seems we have the computes. Cray 1's were used for early simulations, and the box I'm using to post this has 10 times more cycles, and 10 times as much RAM, and its not even a very hot box by today's standards.

This model yields lighter galaxies. How does that affect galaxy clusters?

So, the whole Universe is some 25% less massive. That's some kind of a Universal Weight Loss program.

The Milky Way is nearby. NGC 3031 appears to be M81, a galaxy so bright that there are claims of people seeing it naked eye. NGC 3198 is mag 10.9, NGC 7331 is mag 10.3. I'd guess that the galaxies were chosen as bright, more or less face on galaxies, perhaps with good analysis by others.

Dark Matter seems like an ad hoc solution. Dark Energy is another ad hoc solution. There was a suggested solution to Dark Energy, explained as residual local expansion due to primordial sound waves. With both gone, we're left with just the 5 or 6 percent of the Universe that we've been able to directly detect. I'm not taking any bets, one way or the other, however.