Does MOND actually address dark energy in any way? I don’t think it does or is even particularly intended to do so. As far as I know, MOND does not even pretend to have an explanation for Hubble expansion, but if there’s some fringe of it trying to do so I’d be interested to see. There’s no particular need to introduce dark energy into this discussion though. It’s mostly just a different thing.

Dark matter is an extraordinarily strong theory that has a lot of pretty clear confirming evidence. Euclid is out there right now gathering the exact kind of observational data needed to further advance our understanding, which is very exciting since we know there’s fuzzy edges at the fringes that need to be brought into focus.

This paper aside, MOND basically explains the motion of galaxies and little else. Dark Matter explains the motion of galaxies AND a litany of other observable phenomenon. The cutting edge of MOND, as it exists now, still relies on dark matter to explain most of those phenomenon. It has no explanation for the absence of dark matter in galaxies but its presence in things like galactic clusters to trigger lensing effects or the lack of isotropy in the CMB.

I imagine this is how Curtis felt debating Shapley though. One side of the debate shows that their theory explains FAR more, but does require we vastly expand our horizon of understanding. The other says no, I can come up with an alternate explanation one at a time until we do not have to expand our horizon. Ad hoc theories are inherently weak and should be met with skepticism.