It might be related to LVGL version which changed between the default CMake board-template and the Arduino board-template. At least I know about a certain issue (tested it myself) with setting the style of tabview’s ‘checked’ aka selected tab-button, and unfortunately it turned out to be an LVGL-9 problem. Even in the example on their document page this seems to have this issue, compared to the exapmle on LVGL8 document page. The related topic: Tabview "Checked" colors not working on Arduino/ESP32
Hopefully this gets fixed in LVGL versions newer that 9.1…