After comparing the .h files, it seems like I need to add the width and height to the instantiation.
//old Adafruit_SSD1306(int8_t DC, int8_t RST, int8_t CS);
//RK Adafruit_SSD1306(size_t width, size_t height, int8_t DC, int8_t RST, int8_t CS);
//old Adafruit_SSD1306 display(OLED_DC, OLED_RESET, OLED_CS);
Adafruit_SSD1306 display(128, 64, OLED_DC, OLED_RESET, OLED_CS);
Looking at the code for the new driver it appears to be able to handle SPI as well,
but the display never light up.
The hardware I have is hard to change to I2C, so not going to do that (you need to resolder some resistors,
take a look at the attached pic)
I think for now I’ll just revert to the old code.
Update: When digging in the .h files the I found the display can do HW scrolling. And it does have a couple of different font sizes. This was good find to show what the display can do: https://lastminuteengineers.com/oled-display-arduino-tutorial/
So in short, I don’t think I need to specify my own font after all. Thanks for all the help!