Neither gas refining or NCM Lithium batteries use up the cobalt. It gets contaminated and needs re-refining but it doesn't disappear. Would be a pretty poor re-refining process that makes a third of the cobalt disappear. I wouldn't draw too many assumptions about how much gets wasted until we see how much is left after J. B. Straubel has a say. Second, not all cobalt comes from mines in the Congo. I think that a big deposit is currently underway to be extracted in Canada. The mineral can be responsibly sourced and will likely get cheaper as the new deposits are exploited.
Ironically, about the time that we have eliminated children being exploited to mine the stuff, batteries that use none will be available. Right now, LFP batteries are being used for some EVs. I think you mentioned that those batteries are less energy dense than ternary lithium that is currently used in the high performance Teslas. Bear in mind that LFP can be cycled from 0 to 100 % without degradation, while it can have detrimental effects on battery life if you make a practice of such when using ternary lithium cells. Current recommendations are to only use 15 to 80% of capacity when using ternary lithium chemistry so real world energy density between the two is much closer than some would figure.