I recommend that you get these splitters that are 5-1675mhz (designed for MoCA) and replace the ones you have, especially that first 16 port unit. Get a splitter that only has the number of ports you need to connect for minimum signal loss.

Here are some diagrams from GoCoax that might also assist you in your setup. Pay attention to the PoE filters in the diagram that applies to you as well.

Here are some diagrams from GoCoax that should provide some guidance in how to work with MoCA. 5-1675mhz splitters are important as well as the PoE filters as shown in the diagram that applies to your situation.

Here are some diagrams from GoCoax that might help you. Notice that for a DOCSIS 3.1 system which is most likely what you have (2nd house diagram) there is a PoE filter on the input to the modem as well.

Also make sure that your splitters are all 5-1675mhz to support the higher MoCA frequencies.

You don't state which modem/router model you have.