[astroH]

The best evidence for dark matter is arguably the CMB. The strengths of the individual peaks are highly suggestive of dark matter, in particular the third peak. Furthermore, most MOND simulations on cosmological scales still require dark matter (if they evolve the Universe following the Friedmann equation), for example an 11eV sterile neutrino, because there has yet to be an underlying theory that accurately describes the evolution that can reproduce the mass function and galaxy clustering with MOND. This isn't to say that dark matter doesn't have its problem, one of which is the fact that we don't know what it is; however, there still remain numerous candidates that have yet to be sufficiently explored experimentally.

[prox]

Is there a scenario where both could be right in some way, so part due to DM and part due to modified gravity?

[astroH]

Modified gravity is still being actively explored and I would argue taken very seriously but not in the context of dark matter, rather in the context of dark energy. So in a sense, yes, modified and dark matter combined are both possible in the same theory. However, at the moment, there is no real reason to suggest both dark matter and modified gravity are responsible for things like galaxy rotation curves because one of these works just as well without the other. In fact, many modified gravity theories apply "screening mechanisms" so they don't impact galaxy scales

[kwbauson]

Sabine Hossenfelder has a great series of videos about both dark matter and modified gravity theories (https://www.youtube.com/watch?v=FN2d2cmi_Gk, https://www.youtube.com/watch?v=2VNcDoLNJk8, and https://www.youtube.com/watch?v=468cyBZ_cq4). I think she does a very thorough (and relatively easy to understand) job of explaining what both of the types of theories are, the motivations for developing them, and their strengths and weaknesses. The first video is about dark matter, the second is about modified gravity (mostly focusing on MOND), and in the third she talks about how she thinks it makes sense to accept both. Even if you don't agree with her position, her videos are still very informative for anybody who wants to know more.