I think a blocklist of common sources of biased and sensationalized / misinformation sources would be the best option. It would definitely be a ton of work to whitelist every good source, and you especially want to encourage smaller trusted industry-specific sources (think like pv magazine), there are a lot of those small high quality sources that are geared towards industry professionals. With a short blocklist you could probably cover a significant portion of the loudest biased sources of misinformation.
I think they mean something like widevine a la Netflix. Granted there are bypasses for some levels, but that could be a problem imo, iiuc that’s why there aren’t any alternate frontends for Netflix or HBO. I think that would also potentially mean issues playing YouTube in chromium or firefox on Linux if they used L1 (not sure what the current state of widevine on Linux is, last time I had Netflix I couldn’t watch on Linux and had to use my phone or Chromecast)