Most of the issues that affect Windows are not at the top of the operating system, and the root of the problems goes back to the NT kernel. At this point, Microsoft wants to replace its troubled and problematic kernel with the healthy and trouble-free kernel of Linux. So Microsoft won't have to constantly work on the updates, Linux will handle it for them.
In this context, Microsoft has already been doing some of the necessary work for a while. The Windows Subsystem for Linux (WSL) developers are working to map Linux API calls to Windows. In this context, WSL 2 and Microsoft began to incorporate Linux into Windows Insiders and released its own in-house custom Linux kernel to support WSL. Again, the two companies joined forces in different types of business.
In fact, when we consider the claim that "Microsoft can replace the Windows NT kernel with a Linux kernel", this rumor has now become logical and acceptable. If such a deal is made, it is likely that in Windows 11 everything will look like Windows, and there will be no change for users, but it will be the kernel Linux behind the system that runs everything.