I found IPv4 forwarding from RPi 2 to RPi zero via OTG cable as a solution to my question, but there is a problem I cannot solve.
Raspberry Pi Zero works fine with Pi 3 but I can't connect any other device to USB when Pi Zero is connected. When I try to connect any kind of USB device everything goes into a loop of reconnecting (Pi Zero starts restarting itself, keyboard and the mouse suspend every 10 seconds; and if I plug USB drive it goes in a loop of appearing and disappearing fdisk -l).
If anyone thinks it's a power supply fault: I checked three different kinds (including my phone charger):
- 5 V 1.5 A
- 5 V 3 A
- 5 V 3.5 A