About LVGL version resulted questions

Hi all.
I am new to LVGL, and facing some difficulties:

  1. got confused with LVGL and lovyanGFX, how to use it?
  2. the user_setting examples in lovyanGFX, shown how to config device like ESP32+ILI9341 to use LGFX, is this a universal solution to all kind of applications? because some of other examples even left the config to user.
  3. seems no many examples the new version of the Library? so there are lot of compiling errors, do you have a comparing old and new versions?
  4. are there any working example to show JPEG pictures on ESP32+ILI9341 of .ino ?