T-90s and 80s are not “old stuff” hardware. The T-72s and 64s are old technology. If Russia is turning to old Soviet technology, they have burned up their A list units.
“If Russia is turning to old Soviet technology, they have burned up their A list units.”
No they started with their old tanks and didn’t even bring their first modern tank into Ukraine until the beginning of May.
https://nypost.com/2022/05/05/russia-reportedly-loses-most-advanced-tank-in-ukraine/
T-80s and the T-9os are based on the T-72. The T-14 is their only modern competitive MBT, if it is ever produced in any numbers.