Microsoft hides the direct ISO links behind user-agent spoofing. To get the specific :
The 21h2 ISO is a museum piece. Keep it for the virtual machine lab, but wipe it from your production deployment list. Win10-21h2-english-x64.iso Microsoft
If you’ve been digging through the Microsoft Volume Licensing Service Center (VLSC) or an old archive drive, you might have stumbled across the file named Win10-21h2-english-x64.iso . At first glance, it looks like just another Windows build. But in the fast-paced world of Windows as a Service (WaaS), 21H2 is already a ghost. Microsoft hides the direct ISO links behind user-agent
The official way to download the Win10-21h2-english-x64.iso file is through the Microsoft website. Here's how: If you’ve been digging through the Microsoft Volume
Have you found a weird bug or performance quirk in 21H2 that doesn't exist in 22H2? Let us know in the comments below.
Key features introduced (or backported) in 21H2 include: