Uint8Array over SPI

So, I think I found the culprit. I (again) had a look at the display driver specs and on page 16 it shows the cycle graph(?) for the 4-wire SPI interface, see attached image.

Below the graph it says:

CSB can be “H”between parameter/ command. And SCL, SDA, D/C are invalid
during CSB=”H”

That and the rising flank of the CSB signal after the 8 databits on the right, leads me to believe that CS needs to be pulled down and up again for every byte written.

So I changed my write function like so:

function wData(data) {
 digitalWrite(dcPin, 1);
 _spi.write(data);
}
 digitalWrite(csPin, 0);
for (let i=0;i<bufferSize;i++) wData(buffer[i]);
 digitalWrite(csPin, 1);

Now this does not work anymore, because CS only changes once right before all the data writing.

Changed it back to:

function wData(data) {
 digitalWrite(dcPin, 1);
 digitalWrite(csPin, 0);
 _spi.write(data);
 digitalWrite(csPin, 1);
} 
for (let i=0;i<bufferSize;i++) wData(buffer[i]); 

immediately starts working.

I assume that

_spi.write(data,csPin);

also pulls down csPin only once.

So now the questions would be: would it be feasible to create a native SPI write function that pulls the cs(nss) pin down for every byte written and does that make sense?

Would my case still benefit speedwise? Otherwise I would be stuck to my single bytes write algorithm and the speed bottleneck it causes.

EDIT: Just stumbled across Espruinos capability of inline C code. I guess that could speed up the data transfer loop...?