Based on https://greasyfork.org/en/scripts/22308-youtube-whitelist-channels-in-ublock-origin

Allow you to whitelist specific YouTube channels in uBlock origin by adding the channel name or id in the URL.

To do so:

• Open Add-ons manager
• Find uBlock Origin and click Preferences
• Select "show dashboard"
• Click Whitelist
• Type in the following: youtube.com/*user=<channel name or id>