The Russians are trying to sabotage those negotiations.
https://www.theguardian.com/world/20...ions-exemption
Tho frankly the US/EU could, if they wanted to just have bilateral talks with the Iranians and pretty much ignore the Russians. The more complicated bit is whether China is willing to go along with that or not. The issue is that after all the sanctions we kinda made the Iranians dependent on the Russians and Chinese for pretty much everything that they can't make themselves (pretty much everything). So lifting the sanctions on Iran wouldn't quite cut it, we would have to go much further and actually help the Iranians directly, economically, industrially etc...and that's a tough sell in the US as the chances of Israel going along with that are exactly fucking zero.
It's not an effective buffer zone when Russia already has direct borders to the Baltics, Finland, Norway, and Poland (especially if Belarus is a vassal country).
The east European plain goes across Poland into Germany - and that would be the logical attack route for attacking mainland Europe from Russia (and also the route that Russia historically fears attack from); and that way is pretty similar with and without Ukraine.
Clearly most countries prefer that Russia attack some other country than themselves (and especially if it is costly for Russia), but it in no way makes Ukraine some form of a buffer zone.
Unfortunately, if we want the solutions to stick, we have to think long-term. Europe need to increase their LNG terminals capacity. US LNG terminals are at full capacity now with nowhere to go. The problem is that Europe does not have enough capacities to receive all of US LNG. This is good for both countries. Europe can start getting their LNG from US, and US can stop flaring because of overproduction.
Venezuela oil production is currently at 20% of its peak in 2014. Mostly due to sanction. Once sanction is lifted and companies like EXXON and Chevron could go back in, production can ramp up quickly.
Russian oil companies are in deep shit right now. They have been relying on BP & Shell expertise and equipment, and funding for their arctic drilling which is very challenging. Even if the sanctions are lifted today, those won't be coming back anytime soon. If at all. It looks like the world oil giants are turning their eyes to Africa and South America. Arctic oil cost way too much to get out of the ground.