If videos no longer load on LibreTube for you either, as commented in the issue on GitHub, which worked in my case, enabling the use of HSL in the settings solved the problem and the videos load.
Settings > Audio and video > Use HLS: ON
More info: https://github.com/TeamPiped/Piped/issues/3196#issuecomment-1832129059
Not all heroes wear capes…this fixed it, thanks! Man, how I’ve missed LibreTube.