about performance. in theory

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

23LC1024 datasheet says that its "SPI-Compatible Bus Interface: - 20 MHz Clock rate - SPI/SDI/SQI mode" 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));