I’d see if there is a connection issue on the screen cable. The connection might be bad. In addition to this, you might be suffering from the "stage light” issues that were explored by iFixit. If that doesn’t work, try an NVRAM reset, and if it still doesn’t work, the problem is somewhere else.
Ok, I’ve found the answer. If you have a Install macOS Mojave.app file, which I got from somebody else’s supported machine, you can flash the /Contents/SharedSupport/BaseSystem.dmg to a USB drive with a tool like Etcher. The only catch is that this is a recovery partition image, so you the bootable USB will download a copy of macOS from Apple’s servers, but at least it offers the option for machines that don’t support internet recovery, because I don’t own a Mac.