have you looked at a point to point wireless bridge from you router to the listening area? You will need line of sight from the two radios. I Have good SQ with a 60ghz wireless bridge. This frequency dissapates in oxygen so good for short distances.
That looks a lot simpler than what I envisaged from your original description. Personally I would consider replacing the Netgear switch with something like a Cisco Catalyst, and run the fibre from there with an SFP. That eliminates one more device + PSU from the network.
If at all possible you should run trunking. Then it becomes quite simple to put in whatever optical or copper Ethernet cable you need in future, and to replace any that get damaged.
Optical cable is very cheap, so you can always run it loose through the house to trial it. Then if you find it’s not worthwhile, you won’t have ripped your walls apart for nothing.
I’ve run cable thru walls and floors. You don’t have to tear them apart.
Unless the current run of Ethernet was nailed to the studs, which I doubt, all one has to do is attach the fiber at the terminal end of the Ethernet and drag it back thru.
The only trouble might be if a fire break is in place between the studs, but if the Ethernet went thru then so will anything else.
For fiber ports, I suggest this switch -
https://www.amazon.com/dp/B00VPT8VPG/?coliid=I3DVGGFLT5SESC&colid=1SOY5CO8RC7N8&psc=1&ref_=lv_ov_lig_dp_it
At the fiber terminal end install an opticalRendu, and lose the rGen.