Gaurab:
ARM64 is supported, so the 2.2.4 version should work as long as the OS supports the installation of Java (this is why it can't run on iOS and Android). I have an older version with system-wide Java installed on my Rasbperry Pi 3 running Raspbian, but it is quite dated at this point.
I can't speak to the VPN tunnel, but if you can see the printer via CUPS, then QZ-Tray should be able to print to it. This configuration may not support raw printing, as that is done at the local OS-level, and we have had issues in the past sending raw data to shared CUPS printers. Sizing and scaling may be problematic as well.
Perhaps
@Tres Finocchiaro can offer more insight regarding the VPN tunneling, but I would still recommend escalation with Amazon, as this sounds like a very unique environment.
Kind regards,
Lite