These articles really like to hype things up.
The Novocherkassk was a Ropucha-class landing ship. Currently, the Russian Navy apparently has 19 landing ships actively registered (Novocherkassk included).
Its loss, if accurate, is a blow. But a “major strategic” blow?
I doubt Russia’s strategy for a largely land/air war is going to change to such a degree because of the loss of one landing ship.
No it’s not a major blow. Russia has lost a number of such minor vessels.
More significant is that this may restrict the use of the port of Feodosia. Its been attacked before, destroying a missile corvette under construction. A ship that’s just in and out loading and unloading is a much more transient target.
The total number of Russian ships of this class is not nearly as significant as the number they have (or had) in the Black Sea. Access to the Black Sea is controlled by Turkey, and they are not getting any more warships in there. If a country wants a warship in the Black Sea they either build it in a shipyard on the Black Sea or get Turkey's permission to bring it in.
Ships in the Atlantic or even the Mediterranean are not particularly effective against Ukraine which has only a Black Sea coastline.
“Currently, the Russian Navy apparently has 19 landing ships actively registered (Novocherkassk included).”
But it can’t get other warships in to the Black Sea, because Turkey blocks transit through the Bosphorus Straits during hostilities (Montreux Convention). So only those stationed in the Black Sea (or Caspian, which is connected by a canal to the Don River).
The Black Sea Fleet had eight Large Landing Ships (Ropucha Class) before the 2022 invasion. Three are total losses so far. They also have four Small Landing Ship, that are dramatically smaller. The Large Landing Ships are what they need to conduct significant amphibious landings (as were planned, but not conducted against Odesa) or are also used to ship weapons and Military supplies.
Three out of eight are total losses, and others have been reported damaged. There may also be some operational issues (Maintenance, readiness), but that is just speculation on my part.
These ships seem to be a high priority target of the Ukrainian forces.
Perhaps their cargoes are a priority to interdict (e.g. drones, cruise missiles, Artillery), perhaps they want to remove them as a resupply option, in case/in preparation for an attack on the Kerch Bridge, or perhaps they seek to set post war conditions where Odesa will not be easily threatened by amphibious attack. (not likely, because as you note, such ships from the Northern or Pacific Fleets will likely be able to redeploy to the Black Sea, after the shooting halts).