I have the problem that new devices with Alexa metadata are not showing up in discovery.
I see my items get fetched from myopenhab.org while discovery. Is it possible some rate limiting for the lambda? If I fetch the items like the skill does I get 350k data. Is this to big to be handled by the skill?
Have you gone through the troubleshooting steps listed in the documentation? Try to discover a small subset of your alexa-configured devices at a time.
I am not sure where you saw that restriction and anyway the lambda function payload doesn’t come into play when querying for your OH server items during the discovery process. What would come into play is the time it takes for this request to complete as the skill lambda function will timeout after 10 seconds.