That’s great that you’re using a direct ‘wired’ connection between router and Node 2i. I would recommend adding a passive filter like upcoming Muon Streaming Filter from Network Acoustics. I have not heard it yet, but as per my conversation with Rich at Network Acoustics it’s a definite improvement upon already excellent ENO Filter. So I would wait to buy anything else until Muon is available. And then there are additional benefits of adding a Ethernet switch but I defer this upgrade until you get a high quality player like LinQ. The Ethernet switch improvements are mixed bag, some hear positive results and others do not.
I have upgraded from ENO filter to Telegartner M12 switch (you can read further about it in my virtual system) but a straight forward passive filter like Muon should be your next step until you’re ready to upgrade your Streaming player. Then we can talk about adding a high quality Ethernet switch in your ethernet signal path. Hope this helps!