Hi Daniel,
Thanks for posting your concern.
On the
Google Ads scripts perspective, you may try to follow the instruction below.
1. Put the default information of the account's budget to the Google spreadsheet such as the budget name, customer ID and the amount.
2. Then, you may try to implement some of the
SpreadsheetApp sample scripts to retrieve the values from the spreadsheet.
3. After that, utilize the
Budget Performance Report. You may refer to this
sample code on how you will do it on script.
4. Implement a validation that will compare the budget amount returned by the
Amount fields to the values available in Google spreadsheet.
5. Lastly, if the returned value of the report is not equal to the spreadsheet, then implement this
sample code to send an email notification.
Let me know if you have further questions.
Regards,
Ejay
Google Ads Scripts Team

ref:_00D1U1174p._5001UV0ZTs:ref