I have spent some time and made a stub file for the MicroPython port of LVGL. It is not 100% complete but it does contain most of what is in the LVGL module that is created. It also does contain things that are in the LVGL module but are not exposed to the python side of things. I have yet to clean that stuff out. I modified the genmpy script to add additional information to the metadata JSON file and wrote a script that parses that file to create the stub file. It is not perfect but it will make it a lot easier to write python code to use LVGL.
If there is anything that is incorrect or missing and that is not supposed to be in the file you can update it and submit a pull request and I will add the changes to the existing stub file.