I've heard that the Filter Action for Automations in recent FME Server versions has changed to be integrated, as opposed to simply being the FilterMessage.fmw workspace published to the Tools repository. I'm using FME Server 2019.1.3.1 and I found it useful to update the Tester in the FilterMessage.fmw workspace to "Contains Regex" (as opposed to "Contains") so that I could add more complex queries (i.e. multiple strings searches) in my Filter Action in the Automation. I don't have hands on experience with newer FME Server versions, but I'm thinking this might be something to consider for the integrated Filter Action.
Thanks!