Anti-sleep threshold minutes setting

I love Plex, and my only suggestion other than Playback Speed (which many people have already begged for) is:

Nearly every time I use Plex, my Windows 10 PC falls asleep once the final part of the playing video has been cached. This is problematic if I ever want to rewind because the server will no longer respond.

So if I’m watching a workout video and want to scroll back 30 seconds, if I’ve already reached the final minutes of the video, then my PC has fallen asleep, and Plex therefore can’t let me rewind.

I do not want to change my Windows sleep rules. What I want is to have a setting within Plex where I can choose how many minutes Plex should continue keeping Windows awake even after the end of a video.

That way, I could set it to 30 minutes (for example), and there will be no disabling of the Plex controls during the final portion of a video (after Plex has cached the content).

Early 2021 clean-up: duplicate