https://docs.microsoft.com/en-us/answers/questions/597005/how-to-get-folders-and-files-separately-using-grap.html
We already submitted a question about "How to get folders and files separately using graph drives API ?"
and understand current situation that it is impossible to get folders and files separately.
But, it is crucial that we can get only files excluding folders from the application's performance point of view.
From our estimation, if we can get files only excluding folder information,
it may be 1.3 to 1.5 times faster to get and show 500 and 1000 files in our application, respectively.
We hope "filter=folder" parameter will be supported in near future.