Maybe, but that's assuming their war economy lasts for that long, that they still have people to run those things, etc. Besides, Europe was caught with its proverbial pants down; in 5-10 years, they will (should) have their military up to speed again, with fresher, better equipped and better trained people than Russia has. The border countries have all upgraded their defenses already, and if they invade a NATO country they suddenly have all of Europe and - if still applicable at the time - the US on their back.

There are no scenarios in which Russia can have any significant victories. The only thing they maybe have is nukes, but nobody wins if those are deployed.

No, they literally make barely any tanks. What they do is refurbish and modernize post-soviet stock.