Hi there,
My problem is solved now but I am still not sure why. I could share with you what I have done and hope it's gonna help:
I first went to ask a professional. He said that it was probably hardware issues. It could be due to the small memory size. My laptop has 8GB, which is the minimum requirement for ArcGIS Pro 2.8. So it might be that when running Notebook, the memory was at maximum capacity and could not process properly.
I wanted to upgrade it. However, the day before I went to a computer store, I upgraded my system to Windows 11. When I was at the store and trying to show the Customer Service the problem, it magically worked! I am not sure if upgrading to Win 11 and running Notebook are related, but this works for me. So far I haven't met any more difficulties.
Hope this could help you with the issues. Good luck!
Cheers,
C.