Hello @RM_77,
Apologies for the delayed response.
Based on your description, I understand that when end users are assigned to Attack Simulation Training and access the training page via https://security.microsoft.com/trainingassignments, they can see all the other options in the Defender menu on the left-side blade. Please refer to the screenshot below to confirm that we are on the same page.
You are looking for an option to hide or remove these menu options on the training page.
Currently, there is no feature available to customize the Microsoft Defender menu UI to hide or remove options when an end user is taking a training session on the Defender page.
The only available workaround is to use the Customize navigation option and unselect all the items displayed in the navigation pane.
Since the feature you’re looking for does not exist, I encourage you to provide feedback directly to the Azure Product Group regarding this feature request. You can do so via the Azure Feedback Forum, which allows users to suggest new features, propose enhancements for existing ones, and share general feedback. Additionally, you can vote for existing ideas to help prioritize their implementation or submit your own suggestions.
I hope this information is helpful. Please feel free to reach out if you have any further questions.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Thanks,
Raja Pothuraju.