Invidious is an open-source front-end for YouTube which is self-hosted on a wide arrange of instances (https://invidio.us). One aspect of using Invidious is being able to proxy videos through the instance and thereby not having to go through googlevideo.com directly.
At a glance I can see that youtube-dl seems to support Invidious, so the core functionality should be there to harness from I think.
I'm wondering if it would be possible to add proxying videos through Invidious as an option in SVPtube? It'd be a really nice feature to be able to watch YouTube videos via SVPtube while preserving privacy in this way.