@ryosk25
Welcome to Microsoft Q&A Platform, thanks for posting your query here.
Yes, it is possible to customize with group policy.
So you can apply the same customization options on AVD as with regular Windows 10 on a physical endpoint. For example, you can use GPOs to customize the start menu.
Customize and export Start layout (Windows 10).
Refer below on how to customize an image:
https://learn.microsoft.com/en-us/azure/virtual-desktop/set-up-customize-master-image
Hope that helps.
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