SSD1306 driver is Arduino style C/C++ library with unicode support. The library can be compiled for plain Linux (for example, raspberry spi), or you can use it with plain avr-gcc compiler without ...
Raspberry Pi Pico's built-in bootloader allows you to write firmware via USB or SWD. However, in some situations, other interfaces may be useful. Picoboot3 now offers the options of UART, I2C and SPI.