The upside:

The strategic frame, in Jompy's closing assessment: "The loss of the vast Soviet legacy stockpiles means the capability to quickly regenerate after high attritional warfare won't be there anymore for Russia, and they'll have to change their approach to mechanized warfare." Russia is committing the recoverable end of its Cold War inheritance to this one war. There will not be another.

Yeah, but modern Russian tanks break down a lot, these ate going to be a nightmare. Plus the armor is so old munitions probably slice through them.

Plus diesel is a problem all over Russia now.

Still better for Ukraine if they weren't there.