If your use case requires this data in Funnel, you can request it as a custom connector.
Custom connectors and data requests are available only in Business and Enterprise plans.
Reports
Budget Summary Report
Dimensions:
Currency Code
Date
Account Name
Account Number
Account ID
Campaign Name
Campaign ID
Metrics:
Daily Spend
Month-to-Date Spend (Non-Aggregatable)
Monthly Budget (Non-Aggregatable)
How to request this data
To request Microsoft Ads Budget data and other data that has not been covered here, submit a data request.