The current Media Creation Tool usually downloads the latest version (22H2). To get 21H2 specifically, you may need to use a version of the tool specifically built for 21H2.
, finding the specific 21H2 ISO requires specialized methods: Download Windows 10 Disc Image (ISO File) - Microsoft win1021h2englishx64iso microsoft
Windows 10 Version 21H2, also known as the November 2021 Update The current Media Creation Tool usually downloads the