Not sure why everyone hates WiFi, when done properly, it works great, nothing isolates like not being physically connected. However for best speed, and uptime nothing beats a direct connection.
My streamer is about 40ft from my basestation 2 rooms away. Have run a cable, and done WiFi test back to back. On my system, there is no difference between them. My setup is using WiFi. I do have a higher end cable modem, that I purchased and setup. Found a spot where it will provide WiFi to my entire house and garage without any extenders or repeaters.
Fiber is king! Fiber is almost always "best" But real fiber is expensive, like $300 is the start for a good cable without SPIFs. Fiber has 0 noise, 0 electrons, far less jitter (network jitter not timing jitter) and is basically isolation between devices.
Anytime you add a mesh network, it will have some issues. Especially if 2 base stations are constantly doing a "hand off". Mesh needs to be setup correctly, with some overlap, but not too much where devices are constantly hunting between 2 or more base stations.
Adding more equipment is always a bad idea! You want as FEW hops as possible between your modem and devices. Cat6 runs under 200ft do not need anything special. Long runs are the norm in any data center.
The wall outlet plug in extenders are junk, don't use them.
There is 0 need for LPS on any switch gear, unless the wall wart is plugged into your stereo system power. No data center has upgraded LPS, they all use what comes in the box.