Open Netflix
Tap/click your profile icon
Select Account
Find Profile & Parental Controls
Select the profile you want to change
Locate Playback settings
Turn off Autoplay previews (or “Autoplay” / “Autoplay next episode” if shown)
Save/confirm the change
If you can’t find the setting, go to Netflix.com → Account → Playback settings and turn off Autoplay previews there
On a TV/device, open Netflix settings (if available) and disable Autoplay/Autoplay previews for that profile