Hello,
If you look at the datasheet DS11532 Rev 7 / Table 2, the only difference between the tow versions (STM32F769NI & STM32F769AI) is the Ethernet availability.
Also you should take care about the GPIOs used by the different resources used by TouchGFX (DSI, SDRAM etc ..). So if with STM32F769AI, GPIOs still there, normally you can port it directly to your MCU version (STM32F769AI) without issue.
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