I recall when Russia wanted to purchase oil from the UAE, but due to sanctions Russia can’t conduct the transaction in dollars (often or not is used as the intermediary). Instead the Dirham was used as a replacement currency to acquire it, however it involved exchanging each other’s currency. I mean, why can’t just countries use each other’s own currency to purchase oil to steer away from the petro-dollar?
In that case, counties will just exchange each other’s money directly (like for instance if Germany wants oil from Oman, then the transaction is done via Rial to Euro and vice versa) would that mean it’ll be a multipolar economy since each nation uses their own currency to pay for the imports rather than using US Dollars so much? That was the move BRICS used on them trying to not rely on USD a lot.
The problem is the other side:
The seller has a huge interest to not deal with too much fiat exchange. There’s always fees and market risks associated.
The USD historically was very stable compared to the rest. That in combination with the huge purchasing and military power the US represented while being reliable as a trading partner pushed the US dollar into focus.
The USA then spent a lot of time, energy, money and lifes (mostly others) in ensuring this dominance.
Think of it like a language: a Spanish and a German work together in English - not because it’s impossible for them to learn each others language but because the overhead is too big.
Specifically to your example: no one wants to sell anything to Russia in rubles.
Imagine this scenario:
Hey, I’ll pay you 100 YC (your currency).
Oh since we agreed on the price a few days ago it’s only worth 80YC.
Oh now it’s 120 YC but no one else will take the currency I’m paying you in except me.
Oh now it’s worth 10 YC but we signed the contract, hurray!!