Sure, currently they cannot make more than 200ish tanks a year, but if their stockpiles start running low, nothing stops them from mass producing shitty T55-alikes. Would those be useful against a par military? No way in hell. Would they be enough to enable zergrushing like at Avdiivka? Possibly.
At any rate, I wouldn’t count on the russian army running dry. Currently the western aid running out is more likely, sadly.