Dear aseman,
Currently, Microsoft’s public download channels—including the official Windows Evaluation Center—offer only the latest LTSC release, which is version 21H2. Older LTSC versions such as 1809 are no longer available through standard public download pages. Access to archived ISO files typically requires a valid subscription to either the Volume Licensing Service Center (VLSC) or Visual Studio Subscriptions.
If you are not affiliated with an organization that provides access to these portals, we strongly recommend avoiding third-party download sites, as they may pose risks to system integrity and licensing compliance. For evaluation purposes, you may consider downloading the Windows 10 Enterprise LTSC 2019 Evaluation ISO, which corresponds to version 1809, directly from the Evaluation Center. This version offers a 90-day trial and can be extended for testing scenarios.
I hope this helps. Just kindly tick Accept Answer that others in the community facing similar issues can easily find the solution. Your contribution is highly appreciated.
Best regards,
Domic Vo