about performance

[blinkinglight]

But be aware this is not the fastest way to do it because of that (setting the address for every byte transfered)

23K256 datasheet says that its "Max. Clock 20 MHz"
so SPI.beginTransaction(spisettings) this this, even on arduino uno SPI can work at about 8Mhz speed https://github.com/arduino/ArduinoCore-avr/blob/master/libraries/SPI/src/SPI.h#L74
if you have chip, maybe you can test with

SPI.beginTransaction(SPISettings(20000000UL, MSBFIRST, SPI_MODE0));

i dont have this chip, so i cant test real performance, but maybe for someone this will be usefull