+1, @david_ten
For grounding router / power supply and using better DC cord for LPS. There are quite a few choices or ways to properly ground the router and LPS that does not cause any ground loops and improve the overall performance. I found passive grounding from natural ores to be most effective in my system.
I have gone through few filters and Ethernet switches in my system and results varied based on quality of the components. Bottom line, you will find your best configuration by trial n error.