I have a 2012 Macbook Pro, the one just before the Retina came out. I did not want to upgrade it because this one has changeable Ram, hard drive (now SSD) and the case is good. I guess u already know that Big Sur won’t run on it. I use Catalina. It has a 15 inch screen. Do you think that something inside could be upgraded to a later motherboard or chipset? I only use Bluetooth, wifi and a USB thumb drive. I don’t need anything else to work for peripherals