Using Azure Entra ID I cant see Office 365 Exchange Online under 'APIs my organization uses'

I'm using Mailkit to try and read a free MS outlook email account via IMAP.

Now that App Passwords no longer work with outlook apparently we need to use Entra Id.

I'm following this Mailkit guide. I created a new free Azure subscription so as to use Entra Id.

During registering an app in Azure with IMAP access or ReadEmail permissions the Office 365 Exchange Online API is not listed under 'APIs my organization uses' nor is it under the Microsoft APIs screen

How do I activate this Office 365 Exchange Online API in Application Permissions?

The image below shows all the listings under API's my organisation uses that I'm able to see

The advice is that I need a Microsoft Entra ID P2 licence, now when I try to add this I get the following issue:

The Try/Buy button is greyed out, the message says to Goto M365 Admin Centre to add a licence (see image below). When I do I'm asked to sign in again but them I get the error:

You cant sign in here with a personal account, use a work or school account instead.

but I don't have a work account and when I google this message the advice is to get an admin to create one but I am working solo on this issue and I'm not part of larger company with an admin.

Do I actually need to create a MS work account to add this licence or is there another way using my MS personal account?

The P2 licence is a trial and there will be a charge (see images)

Clicking on More Information and we get this screen (see image below)

My desktop app will authenticating users via Entra ID OAuth so they can read their own Outlook email accounts via IMAP but I'm confused as to how the charging works; some users don't think I will be charged, but I'm not understanding how this pricing model then works?

To enable Office 365 Exchange Online API permissions the tenant must have Microsoft Entra ID P2.

After activating the license, you will be able to assign the Office 365 Exchange Online API permissions: