Anaconda3 Spyder doesn't get launched

Question

I was using Spyder with Anaconda3, and... since this morning, it doesn't get started. I tried to run it with console, and it shows me

ModuleNotFoundError: No module named 'PyQt5.QtWebKitWidgets'

I've searched the solutions and tried to

pip install PyQt5
pip uninstall PyQt5-sip
pip uninstall PyQt5
pip install PyQt5

and ran it again, I got this

qtpy.PythonQtError: No Qt bindings could be found

I deleted Anaconda3, and reinstall with newer version. (2021-05 version)

But this phenomenon sustains... Not sure which have occurred this. I'm looking into Issues in https://github.com/ContinuumIO/anaconda-issues/issues?page=4&q=is%3Aissue+is%3Aopen, but not sure what to look for.

If there is a known issue-solution or a page that I can get help, please let me know. It will be much appreciated. Thank you.