Noticed this linked on Reddit:

https://techcommunity.microsoft.com/t5/microsoft-learn-blog/introducing-a-new-resource-for-all-role-based-microsoft/ba-p/3500870?s=09

In short you can have access to https://learn.microsoft.com while sitting the exam.

I got my AZ900 last year and looking at doing AZ104 next, having the learn site available would be a great help.