I'm not sure what they have to do to fix windows 10. when it launched a few years ago, they were on the right track at reducing the clutter and bloat. the installation was fairly small and the system usage utlization was on par with many linux distributions.
Fast forward to today:
Windows10 is now as bloated as ever. More so than any windows that comes before it. Basic install takes anywhere from 30-40gb of disk space. Up from the 10-20 it was at launch.
At shipping, even without vendor bloatware, Win10 is using 2.5-3.5gb of RAM on it's own (removing default built in bloatware will reduce this to about 1.5).
the patching cycle is more intrusive than ever, especially on mobile devices where you can find your battery disapear instantly when windows decides for YOU when it's going to actually install patches in the background.
As a system administrator who supports hundreds of windows devices, i can say that it wasn't this bad 5 years ago. the lat 3-4 years from Microsoft have absolutely been the worst and most deplorable deployment routines I have encountered.
Everything they do now is Opt-Out instead of opt-in. having my users devices all suddenly using 300ish more RAM because they decided to push out another useless feature (weather/news on the taskbar) as a default ON feature is another example of Microsoft's software developers being out of touch with users and system administrators who have to actually administer this crap.
If There's a "win11". it needs to be yet another fresh start like windows 8 was from a kernel / internals perspective. Whatever has happened with Windows 10 is a complete and utter lack of proper direction from Microsoft. Heck, I have even had conversations with senior engineers there after raising several tickets about complete oversights in their back end that make system administration near impossible (Like the news feature being rolled out weeks/months before the ADMX files for GPO, resulting in a sys-admins inability to remove the news feature via GPO until they caught up)
I used to defend a lot of windows stuff. I still think it's a good OS if you're just a basic user who doesn't nothing other than run games or your standard office stuff. But they've gone right back down the spaghettification of the system, resulting in vast bloat, horrible backend experiences, and a nearly completely unmanageable set of tools from system administration.