My takeaway from testing was basically that it seems Red Bull failed both to make the car more predictable as well as make a sufficient step in performance.
The RB20 was probably at its worst around Monza last year. They recovered some driveability with their Azerbaijan and Austin fixes, but to me the RB21 didn't seem any better. Sure they might've tried extreme setups day 3 of testing, but you don't put on a new component such as a floor or front wing and knowingly drive out with an undriveable car. You'd make a small adjustment to stay inside a balance window, otherwise you're testing worthless configurations that wouldn't be suitable to race anyway.
It's concerning that they haven't been able to improve kerb riding since 2023. Last year Wache specifically said ahead of the season that they had aimed to do just that but it didn't work out.
I think Mclaren will run away with both championships early in the season. Question is how they adapt to stricter wing load testing and possibly less flexible wings.