In PowerAutomate, you should be able to create one or more workflows to extract data from each MS Project and merge them in a single spreadsheet or create individual spreadsheets per project if they don't have the same data structure.

After that, you create a PowerQuery to consolidate and clean your data (using the above spreadsheets as a source) in your desired format. Once the entire workflow is in place, you can manually trigger updates by refreshing the queries in Excel. This is what I usually do for work - I place my source spreadsheet files in a directory that I own in Sharepoint. Then, I can quickly grab the live version of Excel via PowerQuery at any moment.