Power BI is mainly descriptive i.e. they help us to describe current or past state but they are not designed to provide us the reason for the numbers and analyze deeper more than visualizations.
Power BI doesn’t help to gather or consolidate data especially to perform planning, budgeting & forecasting since they are not designed for that.
Companies use a different type of tool called CPM (Corporate Performance Management) for data gathering, consolidating, analysis, budgeting, and forecasting.
To understand more, I recommend this Power BI Training by Intellipaat.
Also, watch this video on how to analyze spending data in Power BI with Azure Consumption: