The Soviet shipbuilding industry in the past had never reached the level of naval powers.
And since the collapse of the Soviet Union, Russia’s shipbuilding industry has been even worse. Since inheriting the Soviet Union up to now, Russia has never been able to build any warship with a displacement of more than 10,000 tons. This makes building an aircraft carrier, obviously a distant idea for Moscow at the moment.

The Russian Navy, simply inherits the remnants of the Soviet Navy, and by the 21st century, the Russian Navy has the task of upgrading and improving the huge number of warships from this socialist era. And if Moscow decommissioned the aircraft carrier Kuznetsov, it would mean Russia admitted that it did not even have the capacity to upgrade an old warship.
The Kuznetsov aircraft carrier was once the only warship, helping the Russian Navy implement a carrier diplomacy strategic, while fighting in the Middle East and increasing its influence in the region. And in the future without an aircraft carrier, Moscow will lose an extremely valuable diplomatic card. The current Russian nuclear submarines, although in large numbers, are difficult to perform diplomatic missions like the Kuznetsov aircraft carrier.

The aircraft carrier Admiral Kuznetsov, also known as a heavy aircraft cruiser, has a full load displacement of 58,600 tons, designed and built by the Soviet Union since 1982. This is an extremely special Soviet aircraft carrier. It is not only capable of deploying fighters, but is also equipped with anti-ship missiles, which can sink enemy warships without using its fighters.
Admiral Kuznetsov is equipped with up to 12 P-700 Granit anti-ship missiles, which can destroy targets at a maximum range of up to 625 km. This is a unique feature that only former Soviet carriers possessed. However, the launch tubes and missiles made the Kuznetsov to sacrifice space for the planes. It is only capable of carrying a maximum of 24 carrier-based fighters, much less than other aircraft carriers of its class.
Source: https://military-wiki.com/admiral-kuznetsov-is-the-honorary-of-the-russian-navy-and-cannot-be-retired/