EDIT: Disregard my previous post. I missed some context.
I'm not sure why it's slower for you. Your settings are mostly fine, except you're probably using too many threads. Leave the download threads at 10, and drop the upload threads to 5. Turn off background i/o as well, and you can raise your minimum download to 20MB if that's your chunk size. Those will help a little bit, but I'm sure you're able to hit at least 300mbps even with the settings you're using.
Here is my CloudDrive copying a 23GB file:
