The major problems isn’t Windows 11 usability, although those issues due exist. UI and workflow issues can typically get addressed, or mitigated, by 3rd party tools.
The real concerns are the exponential increases in spyware, such as the AI recovery tool that records all user interactions, or the native advertising inside of the system itself e.g. Start Menu ads.
If native AI data collection and advertising is baked into all nooks and crannies of the system, the ability of users to mitigate those threats becomes extraordinarily difficult, if not impossible to completely resolve.