Malkom thank you for the reply, it looks like some of the things I am trying to do have been misunderstood/described.
I just expanded point 2. I dont need to convert from the pipeline to logstash but the opposite and as I am using a few DATE custom patterns loaded in a directory on Logstash (as you can see from the Logstash configuration I add another patterns dir , also the patterns are below the logstash config in a few lines down if scrolled) so to have a fully functional filter I am looking for a way to load those patterns on ES. This also should allow me to avoid the use of Logstash and just rely on Filebeat -> ES with a pipeline.
David thank you for pointing at those. I might try the SASS on AWS from Elastic too if my credits allow it. My blocker at the moment is described in this "topic" but i doubt moving to the ES services will make a difference