I'm back on the hopium. They'll be reverting to old specs to gather more data at Baku and Singapore and feed back into the factory, and from Austin onwards they will bring parts that primarily aim to reduce instability . So from Austin they can try to reduce the issues.
But this is speaking with a lot of hope. It's very possible that the fixes from Austin don't work, just like the previous updates. That said, everything they do for the rb20 will feed into the rb21's development so it's worth throwing a ton at fixing this car, even if it feels hopeless