It's way better for sure, but to be honest I'm not sure it's totally resolved. It seems like there's still a little exhaust smell, but maybe I'm just sensitized to it and / or it's still lingering in the interior materials from how bad it was before. Doesn't really matter -- that'll be GM's problem after the repurchase is complete.
On the repurchase, it's not quite as good as I originally stated. They are offering everything I paid for the vehicle, including sales tax, registration and interest on the loan for the 39 months we've had it. Minus about $2100 for the 3300 miles we drove it before the first issue. They will not cover the MSRP gap if we use the offer toward a new 2024. That was BS from the initial paper-pusher customer service reps who set up the repurchase process, but are not actually that informed about it.
I made the case that there should be no mileage deduction, because the first issue was a coolant leak caused by an assembly defect (mis-installed hose) that was present when the vehicle left the factory. And I had to visit multiple dealerships before anyone would believe me that there was a problem. I haven't gotten a response on that yet, but even if they don't go for it, $2100 to drive a vehicle 83,000 miles for 3+ years is a pretty good deal.