Hello,
I have looked at the datasheet for the display controller on the display module (ILI9488). The interface type is selected via a set of pins, and as far as I can tell these are not routed to the connectors on the board. I assume that in this case, they are set to 16-bit mode, so it would not be enough to just connect 8 pins.
In case the backlight does not even come on, you can try to reverse the polarity of the PWM pin.
Just for reference, the V1 has never been supported directly by TouchGFX, but Riverdi may be able to help with some of these questions. They may have a solution for you, either by hardware or software means.
If you want to get your V1 working, you should connect all the data pins, define the actual pins used to some that are available in the connector on the Nucleo board and set up the FMC to run 16-bit mode. This should be fairly straight forward in CubeMX, but it is a lot of wires.
I will also reiterate that it is much simpler to debug this if you make sure to keep assets in internal flash until the screen works.
Then, when the screen works, try external flash, and if you have problems with that, ensure that the data you expect is actually available in the flash and also read properly by the MCU.
In the end, you will probably be a lot better off if your second module ends up being a V1.1.