Hello @xiang-xiang-zhu, does installing the requested package give any more insight? (sudo apt install python3-apt)
I'm not seeing a fatal error in your log, it looks like Steam's startup script tried to check for package dependencies, gave up, then tried to run Steam like normal.
Does Steam return to a command prompt after the last line or does it sit there hanging?
What video card / driver version are you using? In the past we've seen nVidia users that recently updated their video driver version hang at this point, where the loaded nVidia kernel module does not match the version of the userspace libraries on disk. If you're seeing that specific scenario, then trying to start any OpenGL application would give similar behavior and rebooting the system is the simplest solution.
If that is not relevant to you, then can you check if any 32 bit OpenGL application like glxinfo from a 32 bit build of mesa-utils works? Unfortunately, Ubuntu doesn't provide a 32 bit build of this package on 20.04, so maybe try unpacking https://packages.ubuntu.com/bionic/i386/mesa-utils/download with an archive utility and using the utility without installing it to the system.
The original Ubuntu is too buggy now.
Do not install packages from internet pages. You have you'r own in you'r distro. Beleeve me, this package are different from those from ubuntu repo.
Use it:
sudo apt install steam-installer
Or just use Pop!_OS, whitch is based on Ubuntu, but bugs-free!
Nothing extracted yet.
Your system information
Please describe your issue in as much detail as possible:
After I downloaded the deb file from the official steam website, I installed steam using sudo apt-get install ./steam_latest.deb, and then I typed steam in the command line, and the error occurred
Steps for reproducing this issue: