The question is not if, but how soon?
Russia will be paying that ongoing bill for a LONG time (50-100 years, longer?).
IMO, Putin does not have much longer to live. With him dead, that will kill the current Russia. Once that happens, the entire country will have a major “come to God” moment.
The international community will finally pull their heads out of their butts and start to get tough with Russia regarding its obligation to rebuild Ukraine. Money owed to Russia for any reason goes to Ukraine. That is a start. It stops any Russian attempt to accumulate foreign currency because that is how most countries want to be paid (NOT in rubles).
Barter may become Russia’s only means of exchange unless they can come to an international agreement to fund the rebuilding of Ukraine over a long time period (50-100+ years). Russian currency (whatever it might be) will have no value outside Russia because you can’t buy anything with it except within Russia.
The construction industry will boom like never before. People, equipment, machinery, building materials, etc will all explode in price worldwide with the massive demand.
I could see lots of Chinese construction crews there, sent by China under contract to earn foreign exchange.
Architects and designers worldwide get a chance to show off innovative designs (good, bad, whatever) they would have to be approved as likely viable before being built.
Cement demand–oh, wow. And so on. Pick your favorite area and make a small gamble for a big return.