https://learn.microsoft.com/en-us/mem/configmgr/mdt/known-issues

Before uninstalling 21H2 ADK need to copy WinPE x86 Data

Copy the following folders somewhere, you will need to put it back on the original path:

D:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit\Windows Preinstallation Environment\x86
D:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit\Windows Preinstallation Environment\arm
D:\DeploymentShare\Boot\x86


Also need to make sure to uncheck the x86 WinPE option in the Deployment Share Properties in MDT