I used to get plagued with 90002s multiple times a night. I refused to believe it was my computer or my router. I've got a pretty awesome new computer and a relatively decent wifi router and Speedtest says my connection is great!

But when I had the opportunity, I had a net drop put in from the router to the wall next to my PC, by a professional so it would be nice looking. (The front door is in the way so it runs through the attic.)

And...... my 90002 errors stopped after that.

It doesn't matter how good your wifi is, it's going to be inherently more unstable than a wired connection.