Your large picture shows a lot of dark black smoke coming from the gas turbine exhaust stacks indicative of a major class Bravo fuel or lubricant fire, probably uncontrolled and midships, most likely in his main engineering spaces. That would render most firefighting and dewatering efforts ineffective.
Additionally, the smaller picture shows smoky marks along the deck edge from inside the ship on the main deck. There are a number of portholes down the length of the hull, and it’s probable that the crew opened them to improve ventilation and visibility. The amount of smudging along the hull indicates that internally, the ship was almost completely inundated with smoke along her main deck. Opening those, since you cannot now see much smoke emerging means that the airflow most likely reversed, drawing air in and feeding the internal fires like a chimney grating or flue.
Lastly, at about midships, just below the last SS-N-12 launcher pair, there is what appears to be a hole and a light internal to the ship which is either a hot fire, or an artifact of the photo. Either way, Moskva had no hatch along the hull there, so I would surmise that this may have been a missile impact and entry point. It’s about the right height for a sea-skimmer, and similar to what we saw on Stark.
If that is missile damage, there were reports of a strong port list, that hole alone if not mitigated, could have been the cause of progressive flooding and eventual capsize. Fires don’t sink ships, but they help. You have to either let the air out or the water in. We learned from experience that you can sink your own ship while trying to fight fires. Another lesson learned from Stark.
Either way, looks like they were asleep at the switch. Their main phased array radar for the SA-N-6 (the big gizmo aft) is sitting fore and aft, meaning it wasn’t being actively used for defense.
They’re sailors, like me, but I’ve dealt with Russians at sea for most of my career and although I should feel sympathy, given what this ship had done, my sympathies are for their families and loved ones.