I wanted to put padding in between the radio button elements but it didn't do anything, by looking at the code it seems that
lv_obj_t * lv_radiobtn_add_item(lv_obj_t * parent, const char * txt)
{
...
lv_obj_set_style_pad_all(obj, 3, LV_PART_MAIN);
...
}
at lvgl/src/extra/widgets/radiobtn/lv_radiobtn.c:96 is at fault, it is overriding the generated style:
lv_style_set_pad_left(&style_screen_radiobtn_1_extra_btns_main_default, 15);
lv_style_set_pad_right(&style_screen_radiobtn_1_extra_btns_main_default, 9);
lv_style_set_pad_top(&style_screen_radiobtn_1_extra_btns_main_default, 12);
lv_style_set_pad_bottom(&style_screen_radiobtn_1_extra_btns_main_default, 10);
...
lv_obj_add_style(screen_radiobtn_1_item, &style_screen_radiobtn_1_extra_btns_main_default, LV_PART_MAIN|LV_STATE_DEFAULT);