I actually went to the A7RV when it came out.  Still, would be nice to get this camera to work again. Would make a great secondary body. Those cameras are expensive, they should last decades not just a few years.

Sounds like the correct fix may be an A7R III.

So I got the camera out of the closet today to try this solution. I am now facing new issues unfortunately and couldn't perform the steps mentionned by masterflai. My Camera still boots up ONLY with knockof batts, the sony ones do not work. In order to get a camera menu showing, I unfortunately had to quickly unplug the USB cable as soon as the screen goes up. Once I entered the menu, I could see that years ago I completely uninstalled MemoryTweaks from it.  I was unfortunately unable to re-install MemoryTweaks. When the camera is connected to my laptop, I briefly see the usb connection screen then it goes to black before I see this USB screen again then black again. Like a boot loop it never gets out of. It's worth noting I hear like a shutter curtain briefly move during that boot loop, like it is stuck but I know it isn't because when I get to power on the camera by unplugin it, I can take photos and the camera functions as lons as the battery last. It's also worth noting that I do not hear a connection has been made on my laptop as you would usually hear when I plug ANY USB devices... I will try again maybe with a different approach but for now, MemoryTweaks has been uninstaleld, camera seems to be in a boot loop...