This model has been in testing for 3 years and it passed all tests so far.
It already past sevral test and it solves a lot of problems that require dark energy or matter. And problems introduced by the James Webb telescope. It also confirmed cosmic chronometer findings on the expansion history.
It does not disprove models, it just shows that dark matter and energy are not needed and explains why we can’t find them.
The general consensus I can find on what defines a galaxy is "Most astronomers agree on these basics: galaxies are massive, gravitationally bound systems of stars, gas and dust, with an important but poorly understood complement of dark matter. " and it’s not agreed because even with the measurements we have some that lack dark matter. So it is a good and open question even current theory lacks