Yes, there are a few ways to retrieve the DAX formula for a measure in a Power BI report:
Query Editor: If the data source is an Excel workbook, you can access the formula using the Query Editor in Power BI Desktop. Go to Home > Get Data > From File > From Excel and select the workbook. In the Query Editor, you can find the formula in the Applied Steps section.
DirectQuery/Live Connection: If the report is using DirectQuery or Live Connection, you can retrieve the formula by connecting to the data source (e.g. SQL Server database) using SQL Server Management Studio or another tool. The DAX formula is stored in the database and can be retrieved using a query.
DAX Studio: If the report is using Import or DirectQuery/Live Connection, you can use DAX Studio to retrieve the formula. DAX Studio is a free tool that can be used to connect to a Power BI report and retrieve the DAX formulas used in the report.
Note that if the original report was deleted, it may not be possible to retrieve the DAX formula without access to the data source.