Google App Script: Open Google Sheet, wait for all formulas to process, close sheet

Solution 1:

The script will not cause the formulas recalculation as it's not doing any change to the spreadsheet, by the other hand and more importa is that using the results of formulas from a spreadsheet that takes more than few seconds to recalculate as the data source for Google Data Studio or any other similar tool usually is a very bad idea because they don't offer way to control how much time wait for the recalculation to finish and Google Sheets doesn't include a way to be certain that there isn't a recalculation in progress or if the last recalculation has finished other than polling a "witness" (a cell that you know that will change at the end of every recalculation).

Considering the above it's very likely that your "best" option is to transfer the job done by the formulas to the script rather than using something like Utilities.sleep(100000)