Hi Ferrol,
Given that the videos are hosted in YouTube, I think there's nothing OutSystems can do about it because the playback speed is saved in your YouTube (Google) account settings. OutSystems just embeds the videos in its pages.
If you say you adjust the speed for every video, I guess you open each one in a different browser tab (am I right?), so if you watch all the videos in the same tab instead, the playback speed of a video will be the one from the previous video (you can try that in YouTube itself).
Hope it helps.
Cheers!