I generally like that 686 so far. Though it has some audio-network-sharing features I wish I could turn off, like its built-in Chromecast feature. Since that Chromecast feature is audio-only, no one in our household ever casts to it, and it just clutters up the list of available Chromecasts. Occasionally someone mistakenly tries to cast a YouTube video to it, and doing so changes the input.

One "cheap" solution to the CEC issue is what I've implemented on that older Onkyo at the GF's house: A remote christmas-lights-controller switch. Lets me bounce the power on the sucker without having to dig at the rat's nest of wires back there. Any time I have troubles with the CEC, it's two button presses on that fob. It sucks having to keep that fob at the couch, but it beats spelunking for the plug every couple of weeks.

I'd buy a different stereo to replace it, but I have no guarantee a different one won't encounter the same CEC problems. Especially since you have evidence that the problem could be (at least partially) due to the TV at the other end of the wire.