Whatever you are referring to happened while I was on my last break, I think, since it isn’t ringing any bells. The only recent testing I can recall related to performance were for either client-side effects or non-combat performance (like the demo chips and servers for market performance improvements that were tried in mid-2020, and the ongoing suspension of bounty payouts and proactive kill right notifications to improve client-side performance).
Edit: Aether Wars? No news on that front as far as I know - per the @CCP TIDI Eve Server Hardware thread it isn’t something that could realistically be installed directly into EVE in its current state - it would be more like a full migration into a new codebase. I think we’d have to see a suspension in new content deployment for a while for it to happen, because otherwise the new codebase would never be able to get done and caught up to the current codebase for a Lift & Shift style migration of the various databases (accounts, characters, assets, etc).