Russia's deadline for unfriendly countries to pay in rubles coming on Monday. More drama in the fiat world, i see a lot of people panicking about inflation, food shortages etc... But oddly i'm somehow at peace, wondering why that might be

Not going to happen, imho.
They were saying that they would pay bonds in rubles too, then paid in $ and euro.
I am not sure why their contracts stipulated ONLY $ and euros, apparently, but they are valid contract nevertheless.
You can't just ask to be paid in rubles when the contract says: euros (for example).
There might be willing intermediaries, though (for the low low 5% or something).
Also not familiar with the terms and it might have to go through courts, but frankly once you steal/freeze someones money I can't imagine many people expecting Russia to continue to deliver tangible resources in exchange for imaginary units which it cannot use. Default is just a financial term, it implies that entity cannot pay it's debt. It's an indicator that such entity is a high risk, and shouldn't be dealt with unless you want to loose your money. Not sure how much creditors will care if Russia is financially solvent and pays its debt (in convertible yuan or with rubles with say set conversion rate to gold), but is forced to technical default just because US decides not to accept/process it's payments in USD. Business is business.
I understand that EU oil/gas reserves are pretty low coming out of the winter, think few countries even switched to spot for oil deliveries, not sure about the length of current contracts, but alternatively Russia can agree to continue accepting USD/EUR for bare minimum deliveries on current contracts but force any new contracts for next winter to be done in RUB. I expect everyone here is well aware that trades only happen when it's beneficial to both sides. When one freezes all trades but leaves oil/gas, logic dictates that stopping these trades would hurt them more than the adversary. Russia was running surplus even before these high oil/gas prices, their main imports were
machinery computers vehicles etc which now they cannot import anyway, they literally cannot spend the money that they're getting from their exports. Shitty part about sanctions is once you applied them all you have no more leverage. I wouldn't want to be on the EU side during these gas/oil contract negotiations:
EU: so here is our proposal, we just add binary bits in a computer which you cannot use and you send us that sweet sweet oil and gas so out heavy manufacturing can continue to operate and people won't freeze next winter.
Russia: (
slowly opens its fly and whips it out) no, no, please go on, continue, what else would you like...