The only safe source is Microsoft’s official distribution channels: the , Visual Studio Subscriptions (formerly MSDN), or the Media Creation Tool .
As of 2024, Microsoft has transitioned most Windows 10 versions toward their End of Life Home and Pro Editions : Support for 21H2 ended in Enterprise and Education Editions : Support for 21H2 ended in win1021h2englishx64iso microsoft
If you have specific licenses, you can download historical ISOs directly: Best for Enterprise editions. Report: Windows 10 Version 21H2 (English x64 ISO)
The is the standard disc image used for 64-bit systems. It allows for: Visual Studio Subscriptions (formerly MSDN)