Looks like Russia is losing their largest Nuclear Submarine, as reported in Newsweek:
"Following months of speculation, Vladimir Maltsev, head of the Russian Movement for Navy Support, confirmed to the Russian press on Monday that the country's largest nuclear-equipped submarine, the Dmitry Donskoy, was officially being decommissioned. The craft was the last of Russia's Cold War-era Typhoon class of submarines, which were recognized as the largest in the world in terms of tonnage."
And with the Dimitri Donskoy now out of commission, the largest Russian sub is now the Belgorod- an Oscar II-Class sub, commissioned in July 2022. According to Russia, "it is capable of carrying the Poseidon nuclear-capable underwater drones, which Russian naval forces have hyped as a 'weapon of the apocalypse'."
The US Nuclear Powered Submarine fleet, remains very capable and lethal with the newest American submarine, the Columbia class, coming online in 2031 to replace the venerable Ohio Class submarines.