Unless you need to connect other LAN components in your office (which need to communicate to each other), a network switch is likely ’overkill’ for your specific application (i.e. solely for the Antipodes K40).
However, if you are prioritizing sound quality improvements it may make a difference. Make sure you are using decent LAN cable from your basement’s router to the office. Hopefully you are doing that already. If you are not, then I recommend doing so first...before you start adding on passive filters, a switch, etc. [Note: go direct from the router (I'm assuming you have an extra LAN port on it) to the K40. In other words, do not run that cable via your patch panel]
@nmolnar ’s suggestion to look into a fiber optic solution is a good one.
There are many ways to approach this. I believe you will be able to improve your sound quality. One example, having a separate (dedicated) network for your music streaming (separate from your other home and office requirements).