This is so cool! I always dream of doing this but don't know where to start. Even using old LCDs for new and interesting form factors would be a dream. Nice work on this!
But if you just want to get going, you don't really need to go through that sort of trouble. You can just buy a panel + controller board via a retailer like e.g. Waveshare, and hook them up to a computer. Quite a few of these controller boards even have HDMI input, or come with SDK code for e.g. Raspberry Pi if they use SPI over GPIO. You can tinker quite a bit without things getting more challenging, and if you can arrange for wired power you may not really need to optimize anything.