I actually credit Nadella with restoring some amount of Microsoft's reputation. It was Nadella who, on his first year after taking over from Ballmer, stood on the stage in front of a big "MS (heart) Linux" banner and talked about how Microsoft was going to be doing more in the Linux world (I don't recall details). That was also when Microsoft started publishing more things as open-source: VS Code, almost everything related to C# and dotnet... None of which, I believe, would have happened with Ballmer and his mindset at the helm. That was the point at which I stopped saying "Oh, it came from MS, it's going to be low-quality code". Some of their code is halfway decent. Of course, none of the code I consider to be halfway decent is part of Windows...

EDIT to add: I agree that they've been going downhill the past few years, though. And I don't think it's a coincidence that that corresponds with the tendency for some devs (not all, thankfully, but too many) offloading too much of their thinking to LLMs and uncritically pushing insufficiently-reviewed slop into the code review process. I suspect MS has the same problems as other companies with that, perhaps more because of internal pressure (I assume, I have no insider knowledge) to use Copilot.