I bought a RPI Zero for some projects. The problem is that this version of RPI does not have WIFI and only USB is used for keyboard.
Is it possible to install software like pip3
/ guizero
/ ... via SD card?
Yes, but I don't recommend it. You can download the .deb files, copy them to the sd card, and install them using
dpkg -i <package name>
But this has several disadvantages. You cannot use apt package manager without internet connection. You need to install all the dependencies as well, thus can be 10 packages or even much more. And you would need to update manually as well ... a nightmare.
Your options apart from this, you need an USB hub:
1) Get a cheap wifi stick (about $5) 2) If you have your mobile phone, you can enable USB Tethering. This will share your phones internet connection with the RPi. Comment if you need my help to configure this. But it's easy.