"all known opt-out telemetry from Microsoft"
Not all of that is made visible via the phrase "opt-out". Much of yourthe common user's options out of Microsoft telemetry are not told to youthe common user by Microsoft.
The
There are some options that are made available by Microsoft, which are for administrators that should understand the consequences of activating those options. Most of these options have been around since Microsoft Windows NT 4.0, which was (and still is) very powerful and was (and still is) very stable and was (and still is) pre-meditatively anti-hacker. I have never witnessed an NT 4.0 server bank set up correctly that has ever been hacked in all the following years. Thus, there are some options, made available by Microsoft, which Microsoft does not openly advertise to the average and possibly clumsy user. Many are still there in current versions of Microsoft Windows. In the days of NT 4.0, a network administrator had the ability to totally stop all intrusions including Microsoft themselves and every last one of the alphabet agencies. I have seen it done. Unless a user has UEFI on their system, then I suspect that is still the case, but can not herein prove it to you.
The following should take care of a of the small amount of (Microsoft shown) "opt-out" and the large amount of the rest that you can option out of because Microsoft grants to administrators those further options.
Back up data via copy and paste, not using Microsoft's backup.
Format (NTFS) the hard drive or ss drive.
Start the computer with NO Windows install disk in it.
After BIOS has started, then input the install disk (not before).
From BIOS (and only from BIOS) install Windows.
A little levity: No UEFI. Ooops No wait what? But the bright light bulb that we are supposed to fly around says that we "want" to use UEFI! What? Then NO ONE (not even the alphabet agencies) will have UEFI access to read and change and add-to your computer for their [whatever] reasons.
Search the internet for how to manually input blocks to Microsoft (and others like Intelsome CPU companies and some video card companies) telemetry. Then do that.
That should get you about as close as you can get.
Catalog your steps for this, then write a stand-alone C++ program that does all of your work to adjust your (no longer owned due to currently being released as software-as-a-service) Microsoft Windows 11.
Publish the entire code here.
+++ EditI edited the wording of the previous for more clarity.
+++ Also, now in response to Community Bot response for more details.