A couple of thoughts:
- a mesh system may improve on a wi-fi extender (more expensive though) - I use a short Ethernet cable from a mesh satellite to stream to my second system and have had no operational problems whatsoever, but I have not critically listened to the wired vs. wi-fi SQ comparison
- if worried about RFI/EMI, you could convert to fiber at your router, run fiber to your system, and then reconvert back to a short Ethernet cable - I have both but in direct comparison find the difference subtle if not indistinguishable