Empty response for data studio assets search API - google-cloud-platform

Question

I am trying to fetch the data studio assets to manage the permissions based on that data through APIs.
I am using oAuth2 access token generated using the service account as I want to automate this process and not rely on user consent for authorization every time. oAuth2 authorization using service account
Steps I have followed:
Created service account in Google cloud and enabled Google Workspace Domain-wide Delegation
Delegating domain-wide authority to the service account through Google Workspace account
For the following scopes:
https://www.googleapis.com/auth/datastudio
https://www.googleapis.com/auth/userinfo.email
https://www.googleapis.com/auth/userinfo.profile
openid
Created and signed JWT
Used JWT token to get the oAuth2 access token to make Datastudio API calls.
Using the following snippet to generate the signed JWT.
import jwt
import time
import json
import requests
iat = int(time.time())
exp = iat + 3600
claim_set = {"iss": "datastudio-manager#data-project.iam.gserviceaccount.com",
"scope": "https://www.googleapis.com/auth/datastudio https://www.googleapis.com/auth/datastudio.readonly https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/userinfo.profile openid",
"aud": "https://oauth2.googleapis.com/token", "exp": exp, "iat": iat}
encoded = jwt.encode(claim_set, private_key, algorithm="RS256")
response = requests.post("https://oauth2.googleapis.com/token", params={
"grant_type": "urn:ietf:params:oauth:grant-type:jwt-bearer",
"assertion": encoded
})
print(response.json()["access_token"])
Using token generated from above step to make API call.
curl -H "Authorization: Bearer <access_token>" https://datastudio.googleapis.com/v1/assets:search?assetTypes=report
Response of the above request is {} with status 200 and when I am trying to view permissions for a particular asset it is giving me the following response.
API endpoint: https://datastudio.googleapis.com/v1/assets/<asset_id>/permissions
{
"error": {
"code": 403,
"message": "The caller does not have permission",
"status": "PERMISSION_DENIED"
}
}
Is authentication using access token generated through the above oAuth2 method supported for Data studio APIs?
Any leads are much appreciated, thanks in advance!