This is going to be a long and tedious process but is the safest & easiest process to have a usb persistent zorin os 17 on any usb stick with usb 3.0
Before i start let me make you aware the installation and running the os would take atleast 32GB disk space.
Prerequisites : rufus, usb 3.0, zorin os 15.3 iso
Installation: burn the iso into usb using rufus, choose seetings as below
GPT, persistent storage : 20+ gb and press start.
After flash is complete
Boot into boot manager using f12...
Boot into linpus lite.
Instalation screen pops up, choose partitions as : 20+gb : / ext2
500mb : efi
After zorin os 15.3 is installed run sudo apt-get update & & upgrade - y
A new application zorin upgrader will appear. Upgrade to 16 then to 17 from the application
And all set. Happy zorin17