Hi @MichaelHan-MSFT ,
unfortunately this is not a satisfying solution. If you add Files.ReadWrite.All there is no need for Sites.Selected.
Files.ReadWrite.All allows you to list sites and access to all files.
Using Files.ReadWrite.All may be a security risk, because it also allows you to find site by it's URL and access to all files.
A perfect solution here is to use Sites.Selected to allow upload large files.