Streaming: WiFi or wired??

There’s nothing compromised about wireless if the signal is strong and you’re not using some kind of lossy compression (mpg, Blutooth). Given that, wired or wireless might be slightly better, depending on the quality of implementation in the particular device.

(This is similar to the question of whether USB or SPDIF is better. The answer is the same: it depends on the implementation.)

Audiophiles tend to make hard-and-fast rules about things that are not all that clear. My hard-and-fast rule is, ignore such rules unless there are real data to back them up. Real data does not mean one or a few guys listening to one or a few pieces of equipment and generalizing from there.

I suggest you use whatever is most convenient for you. Happy listening!

The following thread will be of interest:

https://forum.audiogon.com/discussions/better-sound-with-ethernet-cable

The bottom line to my three lengthy posts in that thread is that I agree with what @mike_in_nc said in his post above.

Regards,
-- Al

+1 to @mike_in_nc and @almarg 's posts.

It depends. 

WiFi works just fine if your signal strength is good.  For a system the level of using the Kii Three I would look at the Aries G1 or G2 then you have the option.

I started off wireless and soon got tired of losing the handshake. Much more satisfying experience running Cat8 from an Ubiquiti switch. I think BluOs is the worst of the three player OSs that I have. In it's favor it auto indexes locall files and it plays any service without requiring plugin.
I just ordered a 4th streamer that looks like a game changer. Maybe August.