Distinguish when it starts from when it ends
The inactivity period before Ambient Experience begins and the period before it times out are separate decisions. Read the actual labels shown by the device. Changing the start delay does not necessarily change the later exit behavior.
Use a short idle-state observation after making a supported change. Note whether the screen enters art, remains in an audio display or sleeps. Keep normal programme playback out of that comparison so the observed state is clear.
Choose the useful outcome
If the available behavior does not suit the room, use the documented Ambient controls or turn the feature off. Amazon warns it can increase energy consumption; there is no reason to treat an art display as automatically equivalent to low-power standby.
Keep Home as the familiar route back to watching. A successful idle-screen setup includes an easy exit for the next viewer, not just a background image that appears correctly.
Questions answered
Does every Ambient device have a timeout control?
No. Amazon’s current help explicitly scopes that setting to a particular Stick model.
Are start delay and timeout the same?
No. One concerns entry after inactivity; the other concerns how long the experience remains active.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.