Can you try to revert to a previous snapshot before failed installation? If you don’t have one the import a new custom kali, save a snpashot and try this:
dpkg –add-architecture i386
apt install libgcc-8-dev python3.7
apt install veil -y
/usr/share/veil/config/setup.sh –force –silent
And please show us any errors you get when you rin the above commands.
Don’t use the command apt-get upgarde as this will undo the changes made by Zaid.
Let me know how it goes!