Double check all of your connections to make sure you don't end up doing unnecessary repairs. It's easy to not plug something in right. It's not likely, but there is also a chance you could have knocked the power button off the IR blaster daughterboard. I did this during a repair, and I came to realize how easy it was to knock of the tiny little buttons. A way to test this is to listen or feel for a click when you press the power button. If it is broken, here is the part you will need to fix it: Xbox One S RF Board and IR Blaster
There are several things that may be causing this. It sounds like it may be a problem with something shorting or with the power supply. It is most likely the power supply. Here is the part you will need to fix it if it is in fact the power supply. Xbox One S Power Supply: Internal Replacement Part (ifixit.com)
There is a chance there is an issue with the screen itself. Like jayeff said, you can check the screen with a flashlight in a dark room. If there is no visible picture, there might be an issue with the screen and not the backlight. You can try to reseat the screen cables, as they might have come loose and might not be making proper contact. This can happen when the console is taken apart or dropped. All you have to do to reseat them is to unplug them and plug them back in, making sure they are making good contact and are completely attached.
That screen is broken. That usually happens when a screen is bent or dropped, so it could have been damaged during the repair (or as amazon calls it, the renewal) or during shipping. Unless you want to fix it yourself and void any sort warranty of that amazon provides, I would just send it back.
You may have damaged the screen when taking the phone apart, which means you will have to replace it. There is also the possibility that the display connectors are not seated correctly.
I doubt it. Apple is not very user friendly when it comes to repairs. Also, being that the iPhone 14 Pro has 6GB ram, I sincerely doubt that this phone would support 16GB because it's so old, and that you would ever need that much ram. Like I said, the Phone 14 Pro only has 6GB ram, and it is one of the best perfoming phones on the market.
You may have damaged the screen when taking the phone apart, which means you will have to replace it. There is also the possibility that the display connector is not seated correctly.