Flash bin file from SPIFFS of ESP8266 via serial to Arduino UNO

Hi all, I would like to ask you for help with code which would be able to upload stored bin file from NodeMCU v3 (ESP8266) from SPIFFS (or LittleFS) to Arduino UNO board via serial (rx, tx) communication. I am working on a project for kids and want to avoid installing Arduino IDE, drivers etc... I just want to store couple of compiled projects (bin files produce by Arduino IDE) in SPIFFS (or LittleFS) of NodeMCU v3 (ESP8266). My idea is to use your very interesting project published HERE and add one more functionality to it. It could be just a web button which would upload (flash) the stored bin file to Arduino Uno board (with standard bootloader in it). Same as the PC would do. There could be a web button for every project, it is not so important for now. I would just need a bit of help with the code to extend the existing project with this functionality. The NodeMCU would be connected to Arduino Uno via serial (rx, tx) pins + reset pin, or even better to connect both boards with USB cable. That would be the best solution to really simplify it as much as possible. I have been searching for some time if such solution already exist but did not find it yet. Please would be there somebody able to help me with this project? I would really appreciate your help. Thanks and have a good day.