Chosen Solution

Hi, What is the best possible upgrade for this mac in order to get the latest version of macOS using Dosdude1 patcher or else. Is is possible with GPU upgrade to get the latest macOS with this device? What do you think?

You can upgrade the GPU to a AMD Radeon HD 6770M from your 6750M graphics processor. Not sure if it’s worth the trouble to upgrade since they both have 512MB of RAM. You could technically upgrade to a AMD Radeon HD 6970M with 2GB of RAM from the 27inch iMac of the same year, but I don’t think it would fit, would likely cause overheating, and you’d need to make the firmware work.