There's also "del /f /s /q" to delete just files, followed by "rmdir /q /s" to delete just folders; and there's also "robocopy /mir" with an empty folder as a source. From what I've seen straight "rmdir" is the fastest of these three.
Now I don't know is this makes things slower, but Windows File Explorer by default never deletes files. It just moves them to the recycle bin.
If you want to bypass that step you need to use the Shift + Del keys and for that scenario Windows even warns you the action you are request is a permanent delete.
There's also "del /f /s /q" to delete just files, followed by "rmdir /q /s" to delete just folders; and there's also "robocopy /mir" with an empty folder as a source. From what I've seen straight "rmdir" is the fastest of these three.