I think most of this depends on the quality of your streamer.
I know you said to ignore Wifi issues, which is fine, but for critical path things like my work PC and streaming I stick to hard wired. That way when things don’t work I know it’s NOT the Wifi. Now, as for the rest of it, your stream comes down via a series of switches, possibly dozens, and shares the Internet freeqay with news, video, games, porn and billions of Internet of Things (IoT) devices before it gets to you. The music parceled out and put on the freway to be reconstructed at your streamer. Sometimes packets even arrive out of order, and often several packets don’t even take the same path to get to you but your streamer has to put it all together again in the right sequence. No regenerator or galvanic isolator is going to change that.
At best, at the very best we might be able to reduce the noise, and the risk of a cable based surge. The streamers (video and audio) all work by buffering. They hold several seconds of data in memory and dole it out as the TV or DAC needs it. In live video conferencing the buffers are shorter but still there.
Now, are all Wifi appliances equivalent? I don’t know. It’s quite possible some Mesh devices have a lot lower Internet jitter than others, and therefore are better at feeding your streamer, but again, the streamer should hold several seconds of data, and 100 to 200 milliseconds of jitter shouldn’t have anything t o do with it.
So, I only see two real differences in your options. 1 - Ethernet, 2, Mesh.
The other thing to consider is I really like to keep cheap wall warts outside of my power conditioned audio AC, so I also prefer to minimize devices that could potentially pollute that. That includes PC's, mesh routers, etc. , so IMHO if you can remove all that and stick to 1 Ethernet cable that's pretty good, though I admit to using fiber to air gap my incoming Internet from my Wifi router, but that's for surge paranoia.
