As far as I know, at this time there is no way to send RT webtask logs anywhere. Tenant logs can certainly be sent to datadog, but not webtask logs unfortunately.
You might be able to figure out a way to scrape the raw webtask logs. The raw logs can be pulled from a URL that looks like:
https://${TENANT_DOMAIN}.auth0.com/api/logs/tenant/${TENANT_NAME}?key=${KEY}
but you need the ${KEY} which comes from the RT webtask log extension itself.