I have no experience with setting up Windows after Linux. I’ve always done it the other way around.
However, what version of Windows was it running before? If you haven’t switched the components yet, you can use Windows to make a Windows boot flash drive or DVD officially using the “Windows Media creation Tool.” It’s a free download from an official Microsoft page. I don’t think you needed to buy Windows 11 at all. Both windows 10 and 11 will recognize that your hardware (motherboard mostly, I believe) is registered with a license, and it will simply activate your Windows online, no hassle. It’s like the one thing Microsoft got right.