Irony alert - remember that "Tesla is responsible for Congo childrens' deaths" lawsuit which was flawed for numerous reasons - not simply because by all standards the artisinal mines at Kamoto were illegal mines that Kamoto (which Glencore indirectly owns) had been trying to drive out, but more importantly, because there was no evidence out there that Tesla buys Glencore cobalt at all?
The fact that Tesla is now negotiating with Glencore to buy cobalt for GF3 from Glencore seems to basically confirm that they weren't buying from them previously.
Note: if Tesla buys from Glencore, they will be buying Congo cobalt. That said, Glencore is generally seen as the "respectable" producer in the Congo. They're a British company and run large industrial mines, mine with industrial mining equipment, use large scale processing plants, etc. You're much more likely to use artisanal cobalt buying from Chinese suppliers (regardless of where they claim it comes from) than buying from Glencore.