Hi Marouane ( @Zebra067 ),
I am glad you have seen a good improvement in performance 
not good you are experiencing a crash 
It might be worth enabling asserts and logging for LVGL to help track down that issue?
Also I don’t totally understand your response with regard to versions of files etc. and maybe this could contribute to the crashing also. Here is the SDK I generated on the NXP website a couple of days ago for the newly installed MCUXpresso latest IDE I downloaded. Can you confirm this is the correct version for your hardware. I have imported the projects from this SDK and I have used the project named evkbmimxrt1060_lvgl_demo_widgets
If you can post the link from NXP website to share your downloaded SDK I can also check this also if that is helpful?
Kind Regards,
Pete