Covert Cabal on YouTube (Open Source INTel Analyst) has posted his end of year count on Russian tanks remaining in storage bases.
https://www.youtube.com/watch?v=K8CcuVCDEUw
Bottom line: About 3,000, but roughly half are not economically repairable, and the rest are among the worst condition of those Russia had in 2021.
About 1,100 each T-72s and T-62s, about 650 T-64s, 250 T-80s, and no T-90s remain in storage (again, about half of those totals are probably just good for parts).
About 6,000 were visible outside at the start of the invasion, and estimates vary between about 1,000 - 2,000 more that had been stored inside, which have also been pulled out for service in Ukraine (estimated to be effectively all of those that had been stored inside, now having been used).
So from a total of about 7,500 in storage at the start of this invasion, about 80% of those that could be economically restored have already been pulled - the best first, so quality is now quite low.
The non-economically repairable hulls (roughly 1,500) could be made back into operational tanks, if Russia wants to pay the higher cost, and wait for the longer refurbishment time, which would mean slower output. That is what we are likely to see in 2025 (my observation), if expenditure rates stay high.
We already see the tank shortage on the battlefield operationally, and in the decline in confirmed battlefield losses. Russia can no longer field the kind of tank force that they could in 2022.