Streaming: WiFi or wired??

Yes.  Don't believe your lyin' ears!

There are so many ways to slice and dice streaming. Wired is best, but a solid wifi mesh is excellent. Orbi works well. I run ethernet Cat7 out of the Orbi.Streamer is Ultrarendu from Small Green Computer. Uses Roon/Tidal/Qobuz and my ripped CDs. I run ethernet from Orbi into an EtherRegen custom ethernet switch. It really improves the sound. Then connect Ultrarendu to switch. UpTone audio sells the custom switch and great power supplies. 

Good routers let you prioritize service to specific devices.  I was having weird dropouts until my daughter found a "Max Connections" settings deep down in the LinkSys router configuration that was set by default  to 12.  Upped it to 50 and everything is solid.

+1 to the posts by @darkstar and @electroslacker 

You can also specify priority length of time for when you want to switch between say your audio to the TV etc. Depending on which gear you are using, those settings may be available via a phone based App.

Hans and Darko are two audiophile YouTubers who both prioritize digital audio. They both agree that what comes before the DAC makes a difference. 

In this video Hans mentions that galvonic isolation and reclocking, although helpful, are insufficient to fix all noise. https://youtu.be/d9RSLHOFOTc

Another commenter posted a relevant Darko video earlier, so I won't repeat that one here. 

In my experience, treating a modem and router as part of the source has been useful, and I can say that adding low noise power supplies to my modem and router made an obvious improvement for me. This, in my view, the convenience of wifi comes at a cost. 

I wonder how many different philosophies underlie the various views expressed in this thread in answering the question wifi vs wired for SQ. Here's my attempt to articulate them:
1. Nothing upstream from a quality DAC matters for SQ.
2. Nothing upstream from a quality streamer (or reclocker) matters for SQ.
3. WiFi can sound identical to wired when the WiFi card is well implemented. 
4. Noise is introduced in all sorts of ways upstream, and the tools we have to remove noise can be used farther upstream than a streamer with clear improvements to SQ.