So.... other than setting WiFi to OFF during sleep, what is new here? Everything else has been suggested as a fix and has been shown conclusively to NOT be the fix. Did I miss something?
The problem is that the issue is sporadic and often goes away for a while. That causes everyone who does anything to the phone to think they found THE solution.
Back when I was in college, I lived in a building with an elevator that would occasionally freeze with the doors open. The actual problem was it had a bad cable and it would eventually spontaneously freeze and restart. But everyone who used that elevator had their own unique cure because that was what they did just before it spontaneously restarted