Plex isn’t too bad for displaying your own content, but if you try to watch something that is a series, it’s a big fail. Being older, I often fall asleep in the evening, while trying to watch an episode of a series.
While I’m asleep, that episode finishes, so the next evening I can’t get back to it. This last series It’s jumped me ahead of episodes numerous times, when I haven’t watched the previous episode. So trying to follow the series becomes impossible.
If you’re trying to watch a series, you’re better off downloading it from some of those other free places, and then using Plex to stream it to your TV. This usually skips over all the advertising too.
While the Continue Watching hub might show the next episode based on your „watch progress while sleeping“, there’s many ways to deal with this, e.g.:
open the next episode from Continue Watching, then navigate to the previous episode(s) you had sleep-skipped
use the recently watched episodes hub of the tv library in question, to pick the 1st episode you don’t remember watching because you fell asleep [edit: only applies to media from your own Plex libraries… I had missed this is about Plex‘ online media sources]
use your profile‘s watch history to see what you watched and jump to the first episode you sleep-skipped
There’s also the option to use the Player Experience preferences to enable Passout Protection (requires a Plex Pass) or to disable auto-play in the player on-screen-menu.