There's no such thing as a "Windows computer". They're just computers. You can put almost any operating system you like on them. I haven't used Windows in over a decade.
Seems to me it's all a matter of how one configures their motherboard bios. It's true though, that Microsoft is making it difficult to achieve dual boot of Windows 11 and anything else, but it seems some have found ways around it.
On my primary computer I still run both Windows 10 and Linux Mint 20.3/21.0 using removable SSDs. But every day I seem to find new ways of not needing to load Windows at all.