It just keeps failing when I do sudo apt-get upgrade because it failed to upgrade some package that based on Python3. The error was: undefined symbol: XML_SetHashSalt. I'd been searching around for solutions but there is no such answer on StackOverflow.
Then at the end, I found an answer on not very related question mention that the library path for libexpat.so.1 pointing to /usr/local/lib/ may cause the issue. So I try to rename libexpat.so.1 to libexpat.so.1-bk then it works.
So I just re-post it here, hope it helps for anyone facing it.
It seems that you have broken your system.
If you are using apt, the /usr/local/ should never be used.
If you are using /usr/local/, do not use apt to manage your installation.
Apt-get error "undefined symbol: xml_sethashsalt" when install/update python3