It's hard to find a solution, because I don't know your concept, design, flow and code as a whole, because the multiplayer plugin is very complicated.
I saw that there were several objects that didn't seem to need to be synchronized, events and actions that didn't seem to fit, but I found it difficult to correct them due to the lack of information that I mentioned before.
And it looks like you have to learn the basic principles of this plugin, because it also took me a while to really understand.
But once you understand how it works, you will find this plugin a lot of fun.
Maybe the project you are working on seems more suited to chat mode like the example provided by Construct.