> Russia can't make all of that at the same level as the rest of the world combined.Right now they don't have to, they just need to replace things at the level as Ukraine with just a little help from others. That is much more manageable than “the rest of the world combined”.
> The Russian population is in for a world of hurt.
Which Putin will blame on the rest of the world. While many in Russia are well aware that state run media (and anything else not banned) is often a pile of lies from on high, an awful lot of the general populace are not – disinformation from the top works (and not just in Russia & similar regimes, cf. the cult of Trump) and failing that many people who don't believe the official line will keep quiet about that for reasons of what continued quality of life is possible.
> The Russian population is in for a world of hurt.
The military will do OK for a while at least though. They haven't sent over the majority of their equipment, they'll have plenty in reserve and raw materials for making at least some more. Sales of oil & gas can be funnelled into buying more from outside if needed (massive exchange rate differences don't matter as much if export payments almost immediately go out on import payments, or they can start trading more directly if they have a willing trading partner (China perhaps?)).