At this point, I just facepalm every time I encounter another tumblr post about how to get Windows 11 to not use your data in some security-breaching manner. Maybe it's "how to stop Win11 from training AI on your data" or "how to disable Copilot" or whatever. Yeah. What you said was "How to Make Windows 11 Stop Spying on You". What I heard was "How to Swim in Shark-Infested Waters with an Open Wound Without Being Eaten". Neither problem has a permanent solution until you change something fundamental about the situation.
Any of the so-called "permanent" solutions to keeping your data private on Windows 11 will, at some point, stop working. I recall the solution to stopping Windows Automatic Updates on Windows 10 always began with "first, press CTRL+Windows and enter 'services.msc'". That worked fine for about 9 months, until Microsoft stopped letting you access services.msc on Windows 10. At that point, you were stuck. Software like ShutUp10++ offered Band-Aids to put over the bullethole, but Microsoft finally put a stop to personal liberty and there was no permanent solution that would work for every use case.
What I'm getting at is, you may be able to hide or even on some level turn off telemetry on Windows 11. Microsoft is only humouring you. Whatever you do to hide or turn off telemetry will be turned back on again in short order because their business model relies upon being able to analyse and sell the data that all Windows users since 8.1 have been furnishing them in plenty without their knowledge. In the cases where people did find out that Windows was spying on them, they were outraged! They were livid! They took to the Microsoft help forums and demanded a way to opt out! But ultimately, they did nothing. They moulded their entire lives around their Windows computers and became convinced they could not function outside the Windows shell.
This is partially why I came down so hard on "Scare Tactics": Windows 11 is a large part of Project 2025's automated enforcement framework and the only thing people seem willing to do about it is complain a little bit more. You are not Strong Bad, you are not attempting to answer a fan email from your work computer; you do not have the luxury of complaining anymore. AI training cannot be conducted locally, it must be outsourced to a datacentre with thousands of terabytes of physical memory. Even if you are not connected to the internet at the time you generate personal data, it will be transmitted the moment internet connectivity can be established. If you have a lot of RAM installed, you won't even notice any lag when this occurs. Furthermore, Windows 11 does more than simply train their AI systems on your data; Microsoft receive detailed reports from every instance of Windows 11 about most kinds of data generated by its users. The most common use of this data is behavioural analysis for purposes of targeted advertising, but that same data is shared almost instantaneously with the federal police and spy agencies. Not just in the US, but the European Union, United Kingdom, Russia, Japan, India, anywhere Microsoft has a license to conduct business.
Microsoft ought to shorten their Windows 11 license agreement so it reads, "By using Windows 11, I certify that all users of the device where it is installed shall be an open book to advertisers, government agencies, and anyone else who flashes a briefcase full of cash in our direction. I certify that users of this device shall have no privacy of any kind and that any attempt to gain privacy on this device is a futile endeavour that Microsoft can and will undo nearly instantaneously." Everything else currently written there is pointless, since this says it all right there.
The only permanent solution to getting Windows 11 to stop spying on you is to overwrite it with Linux Mint.