Utilise Power Automate to automatically add data from a new week to table from a json api connection

Hi mphillenga 

Can you try below steps, it may help you.
1. Create Parameters in the power bi file input start date and end date, then publish the report to the workspace.

2. Create power automate flow to trigger dataset refresh,

Create the Power Automate Flow, Add HTTP Flow activity for post method

URI : https://login.microsoftonline.com/{tenantId}/oauth2/v2.0/token

HEADER : {

 "Content-Type": "application/x-www-form-urlencoded"

}

BODY : client_id={ClientId}&client_secret={Client Secret}&scope=https://graph.microsoft.com/.default&grant_type=client_credentials

Replace {tenantId}, {ClientId}, and {ClientSecret} with your values from the Azure portal

3. Get the barrier token from above request and send it to below post request

URI: https://wabi-west-us-c-primary-redirect.analysis.windows.net/V1.0/myorg/datasets/{Datasets}/Default.UpdateParameters

Headers :

{

 "Content-Type": "application/json",

 "Authorization": "Bearer {access_token}"

}

BODY:

{

 "notifyOption": "MailOnFailure",

 "parameters": {

   "StartDate": "{StartDate}",

   "EndDate": "{EndDate}"

 }

}

bearer {access_token} : from previous output

to send StartDate and EndDate pass parameters.

please refer below microsoft document 
Datasets - Update Parameters - REST API (Power BI Power BI REST APIs) | Microsoft Learn

Thank you.