@Dan, Thanks for posting in Q&A. Based on my researching, I find currently, there's no setting for Android Enterprise kiosk devices to set screen timeout yet.
You can feedback to the following link to see if we can get this in the future:
https://feedbackportal.microsoft.com/feedback/forum/ef1d6d38-fd1b-ec11-b6e7-0022481f8472
Thanks for your understanding.
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