Microsoft GRAPH API to get total number of mails in my inbox

I am writing to script to check my mail and download the attachments. What I am trying to do is to check my Total inbox mail count every 5mins and find if there is a new mail and download its attachments.
I am following this python tutorial.
Below is my function to get the total number of mails in my inbox

def get_all_msg(self):
    endpoint = '/me/mailFolders/inbox/messages'
    request_url = f'{endpoint}?$count=true'

    inbox_response = self.user_client.get(request_url)
    return inbox_response.json()['@odata.count']

This returns 1520 but the total number of mails in my inbox is around 250
But if there is a new mail the function returns 1521 (gets incremented by 1 expected)

Not sure if this is the correct approach

Any input is much appreciated