Hi,
I have experience for 15+ years in electronics/embedded development. I have several years of advanced AVR/arduino development, including library development from scratch. Practically all Arduino AVR boards used, like: 2009, 2010, UNO, MEGA, NANO, MICRO, MINI and others like DigiSpark (attiny85). Several shields used like Ethernet (W5100, ENC28J60, etc.) with various IP protocols implementation, various graphical TFTs with and without touchscreen and various BUS types (parallel, SPI, I2C, etc.), all kinds of sensors and buses, serial and parallel memories, etc.
I am quite experienced in using the Arduino IDE for ESP8266/ESP32 boards, as well as interfacing with OLED displays and NMEA compatible GPS modules.
I don't really have the same hardware you have, but I think I can easily complete your project using adafruit's own opensource libraries for both modules, delivering good quality fully commented code and help/support you to get it up and running on your side.
If you are interested in my bid, feel free to contact me.
Best regards,
Carlos.