Since this format is not supported implicitly by ES, guess you need to define your own format in your index template to avoid ingestion failure issues: format | Elasticsearch Guide [8.6] | Elastic
About the other issue where metrics are not being polled, guess there was another issue opened without any responses: Metricbeat error about scanning empty io.stat file - Elastic Stack / Beats - Discuss the Elastic Stack
And I see you have already commented on github issue for this 