@mipstian I'm testing something as a workaround to the "YouTube delays videos in Mac Safari when using Wipr" problem. Seems to work. Maybe it can help implement a fix faster.

1. Leave all Wipr blocklists and Wipr Extra enabled for all sites, including YouTube.
2. Install uBlock Origin Lite for Safari from the Mac App Store.
3. Give that extension permission to access only YouTube.
4. Turn off the blocklists uBlock has on by default.
5. Enable "uBlock filters – Experimental.”
6. Delay is gone.