Okay, okay, I might be able to shed some light on the green flashes....
This happened to me when I switched TVs. It seemed to happen almost like clockwork with temperature change, as the TV warmed up. It would start doing the green flashes about 20 minutes after I turned the TV on, and it would flash for about half an hour (give or take several minutes), enough that I couldn't keep watching as is. Then it would sometimes stop on its own, altho I usually felt compelled to fidget with it.
I'm always analyzing, and I concluded that it behaved like a short in the HDMI 1 input. If I jiggled the cable, and made sure it was pushed in all the way, the green flashes would stop, eventually. But, I usually had to sit and wait to make sure it stopped. Often it would start again and I would have to push it more to the left or more right, while pushing it in, to find the sweet spot. Eventually it would stop.
Thing is, it was never "cured". Messing with the cable always worked, but it would happen again the next day 20-30 minutes after I turned it on--I concluded it was expansion of the metal in the connectors somewhere. I still had picture (somewhat), so it was still connected, but some part was "not quite" there, flashing green on and off. HOWEVER, if I never turned the TV off, the flashing would stop for months at a time!!
The person who had the TV prior was sort of like a bull in a china shop, and I think she yanked on cables indiscriminately, and probably shoved them in forcibly, etc., causing a short. And since the other TV never did it, I don't think it was the cable. I think it was a short in the plug of the TV itself. Hopefully the warranty is still good because I think you got a lemon. Personally, I would report the TV defective and get a replacement. It's a real pain, I know! I feel for you, because when you sit down to watch TV, it's usually end of the day when you want to relax. The green flashes not only ruin that, but the frustration of having to get up and down, up and down, trying to resolve a problem that your not sure what the cause of is... You have my sympathy.
The flasher TV of mine is no longer in the picture. Flashes and frustration are both gone! I hope you find a solution too. ❤️