I've read this thread and tried the solutions listed (restarting Netflix app, deleting and reinstalling Netflix app etc.) ....
But it STILL autoplays when looking at the details page of a title even though I have auto previews TURNED OFF on my profile!
So annoying!
(Older thread: https://community.roku.com/t5/Channels-viewing/How-to-turn-Netflix-autoplay-on-off-on-Roku/td-p/5413...)
I'm on a Roku Streambar Pro
See my response to your question on a different thread.
I did. I changed the setting on the website but it doesn't change on Roku.
I did the steps suggested earlier (deleting Netflix and reinstalling, restting it etc.) and it still auto previcews even though my profile on the web says that is OFF>
I responded on the other thread, but I'll repeat it here in case others are looking for a solution.
Netflix has complete control over the way their apps work on different devices. They are the only one that can make this work the way you desire.