Trouble Uploading PowerPoint addin from Admin Intregrated Apps

Hello,

We're trying to upload a custom addin by the Microsoft 365 admin center -> Integrated Apps method written in the Publish docs (https://learn.microsoft.com/en-us/office/dev/add-ins/publish/publish)

However, when we try to upload an addin, we can only select `Teams Apps` and no other options (the select button is disabled).

See photo below

we also don't see any `addin` options:

we tried to upload our powerpoint manifest while the `Teams App` is selected, but of course we get an unusable manifest error.

Could anyone give us some pointers / reasons why this is?
Are there other documentation on deploying addin apps within Microsoft 365 Admin center?