How much tanks does Germany have, and how much does Russia?

I will do Googling for you.

354 vs 12000

Russia's tank force biggest problem? Having more tanks than pilots.

Half of this tank fleet is in long term storage for this reason, and what's left half is in rather bad semi-written-off condition.

If we let Russians to regain their breathe, it would not take them long to restore them, and regain this enormous military asset.

Russia only has 3000 tanks in service. The rest are mothballed. That's not half, that's 75+%.

Even looking in total, the vast majority of these "12 000" tanks are in fact T-72s, 9000 of them. We already know how T-72s fare against modern tanks.

For sure, 3000 decent MBTs is a formidable force. But 3000 vs 1000 is not going to let Russia steamroll when their air force is set-up for defence and not offense. Even an advantage of 3:1 is not going to do you much good when your opponent has absolute air supremacy.

A Russian offensive into Western Europe will definitely get stalled, there is no question about it.