Thanks a lot for the tests. And it seem that this Waveshare is not something that is recommended for anything fast since it doesn't seem to be the board.
I have tested pretty much all of the examples, takes a surprisingly long time to compile new but to say the least so is it all very limited in speed even with max SPI speed.
You expected about 6 seconds for the 320x480 it but as mentioned its 15.2 seconds to complete. If I remove all the fillScreens its down to half of that 7.2 seconds and close. The screen fill with any color is very slow and probably won't be possible to get any faster on this one anyway and thus the Waveshare can't be used, which is annoying but oh well.
I just noticed that I can also see some ghosting from any white text that have been on for a longer time then about 20 - 30 seconds which i see as surprising, I mean its not a OLED. Its not permanent and can be erased with a white fill screen fex but if on for long times say 20 min, which it was once, its a little harder to erase.
But ok I will buy the ST7796S since that seem to be very fine, just a bummer that it can't be connected directly to the Nucleo like the waveshare. But I guess the long pins can be used for that and thus just a long female pin header, or what they are called.