The last I looked into this these were the conclusions I reached (depending on individual situation):
- If you're looking to do this 100% to the letter, then you'll need to enter some form of VL agreement with an authorized reseller. This will come with a minimum purchase of 5 licenses.
- If you're looking to do this with a "real" key, but not by the book, then one of the gray market sites.
- If you're looking to do this morally (by paying Microsoft), but don't care if the actual activation is completed with the license you purchase, then purchase a Windows 11 Pro license but use https://github.com/massgravel/Microsoft-Activation-Scripts/ to activate your Windows 11 LTSC. The ISO itself can still be sourced from Microsoft.
- If you don't care about any of this, then the same as the above except don't buy the Windows 11 Pro License
- If you absolutely want to buy a single license "by the book"... there is no official offering available.