steam crashes on ubuntu 20.10

When this happened to me I found disabling the auto submit of the password worked. I set the rememberPassword flag to zero in the config file ~/.steam/registry.vdf using nano.

I submitted a similar issue a few days ago so it seems like the latest update broke Steam on Ubuntu for a lot of people.

Steam crashes silently on startup on Ubuntu 18.04 and 20.04 (igpu)

I had the same problem. I fixed it using

sudo aptitude install libgl1-mesa-dri:i386

I don't really know what aptitude is, I think it's just a different kind of interface to apt, but it managed to solve all the problems with unmet dependencies I had when I tried to install libgl1-mesa-glx:i386 using apt.
After this, I ran

sudo apt install steam

and I started Steam via terminal. It installed the other dependencies and now it works!