That is another problem. At the beginning I set the value to 2KB. As always with the ESP32 as well as with the Arduino Mega, error message belongs:
Arduino\libraries\lvgl-master\src\lv_misc\lv_mem.c:122:33: error: size of array ‘work_mem_int’ is too large
static LV_MEM_ATTR MEM_UNIT work_mem_int[LV_MEM_SIZE / sizeof(MEM_UNIT)];
I got around the problem by entering the array static LV_MEM_ATTR MEM_UNIT work_mem_int [LV_MEM_SIZE / sizeof (MEM_UNIT)] in the lv_mem.c file; simply entered 2000 blindly. The code was then compilable. If I bring this back to the old state, the code can no longer be compiled.
best regards
David