"As of 2021, the company's monthly tank production capacity is estimated to be around 30-35 units."
30 to 35 in total is not 135 of a specific model. Russia is rebuilding a lot of tanks, not just building T-90s. The fact that Russia is getting WW-II armor back in service means they are losing modern vehicles faster than their replacements are produced.
Getting T-55s back to the front lines is a clear sign of how much Russia has lost.
You are talking about a single company. That WWII armor is mostly retrofitted into a cross between artillery and tank for mech infantry units.