Granting Azure Application User access to PowerApps API

I have created a single tenant application and assigned it as application user with System Administrator permissions to access one of my Dynamics environments, however I would also like to grant this application permissions to access PowerApps API (https://api.bap.microsoft.com), I couldn't find any informative article to answer what I'm trying to achieve here, and couldn't find a way to add the application user as admin for the PowerApps panel

To be specific I'm trying to perform the following API call using application user OAuth2 token https://api.bap.microsoft.com/providers/Microsoft.BusinessAppPlatform/lifecycleOperations?api-version=2021-04-01.
Response I get:

{ "error": { "code": "Forbidden", "message": "The service principal with id 'bd0000a6-2600-4e10-8d71-6d35e900000c' for application 5a00de00-79af-4400-b003-a3a136b94db9 does not have permission to access the path 'https://10.0.5.63:20062/providers/Microsoft.BusinessAppPlatform/lifecycleOperations?api-version=2021-04-01' in tenant e6000e48-bd54-413e-b005-df000000bd2c." } }

Azure AD application permissions didn't have anything for PowerApps API access (application user) to help me gain this access.

How can I provide access to my application user?

EDIT: I obtained the access token using MSAL Python library, which the very same auth method works fine with my dynamics env URL..

AUTHORITY = f'https://login.microsoftonline.com/{TENANT_ID}'

SCOPES = ['https://api.bap.microsoft.com/.default']

app = ConfidentialClientApplication(
    client_id=CLIENT_ID,
    authority=AUTHORITY,
    client_credential=CLIENT_SECRET,
)
token_response = app.acquire_token_for_client(scopes=SCOPES)

Permissions(I didn't find anything for application permissions for PA):

As I do not have any lifecycle Operations, I tried the sample query to access PowerApps API and got the same error as you:

https://api.bap.microsoft.com/providers/Microsoft.BusinessAppPlatform/scopes/admin/environments/myenv?api-version=2020-10-01&$select=properties/lifecycleOperationsEnforcement

The service principal with id 'xxx' for application xxx does not have permission to access the path 'https://10.0.5.63:20062/providers/Microsoft.BusinessAppPlatform/lifecycleOperations?api-version=2021-04-01' in tenant xxx

The error usually occurs if the Azure AD application doesn't have sufficient permissions to perform the action.

To resolve the error, you have to register the client application ID with Microsoft Power Platform to access the PowerApps using Client Credential flow.

Register an admin management application(Using PowerPlatform admin user):

PUT https://api.bap.microsoft.com/providers/Microsoft.BusinessAppPlatform/adminApplications/ClientID?api-version=2020-10-01

Now I generated the access token using below parameters via Postman:

https://login.microsoftonline.com/TenantID/oauth2/v2.0/token

client_id:ClientID
client_secret:ClientSecret
scope:https://api.bap.microsoft.com/.default
grant_type:client_credentials

Now when for sample I tried to access the PowerApps API and its successful like below:

https://api.bap.microsoft.com/providers/Microsoft.BusinessAppPlatform/scopes/admin/environments/myenv?api-version=2020-10-01&$select=properties/lifecycleOperationsEnforcement

You can generate the access token after registering the application as admin management application and pass https://api.bap.microsoft.com/providers/Microsoft.BusinessAppPlatform/lifecycleOperations?api-version=2021-04-01 to access the PowerApps API.

References:

https://learn.microsoft.com/en-us/power-platform/admin/powerplatform-api-create-service-principal

Programmability and Extensibility - Authentication - Power Platform | Microsoft