What would be the consequences of a drastic reduction of Ukrainian and Russian exports?

In Spain, supermarkets have started limiting purchase of sunflower oil beyond 5 liters per person. It looks like there are supplying problems, since both Russia and Ukraine are the main exporters of this produce. This has immediately driven prices soaring. It has been mentioned that the same could happen with minerals that are critical for the automotive industry, such as xenon.

If Russia completes invasion of Ukraine, all exports could be restricted due to sanctions. Even if this outcome does not occur and the war lasts for some time, logistic problems would avoid exports.

Are there products mostly imported from Ukraine that cannot be substituted? Being in Spain we could use olive instead of sunflower oil (at an enormously higher price) but I guess it is not so easy to replace xenon in some applications.

And, what would be the consequences of lacking such products? Would car makers simply have to stop production, for instance?