Need some advice about my PS4 Pro and what to do next.

I bought a PS4 Pro the day after it came out, and it worked fine for little under a month until I moved into a new house. After I moved I noticed the Pro moving slowly and having texture problems, as it was inside of the return window I took it back and got another one, this one had the same problems, so after a while I finally decided to send it in to Sony, they didn't necessarily say that there was anything wrong with it, but they sent me another one anyways and this one is having the exact same problems. I have tried everything from changing the hdmi cable, and putting the Pro on a different TV, and rebuilding the database. I have checked the voltage from the wall and it is fine. The only other thing I could think of would be the internet that it is on, as that is pretty much the only difference between when it was working to now. Can anyone give me some advice about what I could do to try and see if that is the problem. Any Wi-Fi settings I should be looking into, could an ethernet connection correct the problems? This has been 3 Ps4 Pros and it has become incredibly frustrating that I cannot play my games with these problems continuing to happen.