Bad picture quality with YouTube TV multiview? You aren’t alone

TL;DR

• For the past couple of weeks, YouTube TV users have been complaining about bad picture quality when using multiview.
• Numerous reports indicate that watching a single channel appears fine, but the quality severely degrades when watching two, three, or four channels at once.
• This is reportedly happening even with fast, wired internet connections and with other streaming apps running fine, suggesting it may be an issue with YouTube TV itself.