I had the same problem on windows 10 : after a while all the speeds where on zero. Sometimes restarting deluge was ok, other times a full reboot was necessary, as you. But i finally found the solution for my system (maybe not the same for you) : i had run a few tests with ICS (internet connection sh...

Did you turn off the windows defender ?

Sonarr is the tool responsible for this operation.
If you have correctly configured deluge in sonarr, sonarr will detect the downloaded episodes in deluge (wherever they are) and will move them at the right place for your plex.

try the plugin "label plus"