I want to help a friend who is on the other side of the planet install opensuse. They have a USB stick with the leap15.2 ISO burned. I read a while ago (lost article now) that it may be possible to ‘enable’ a VNC host in the Boot Options on the Graphical Boot Screen. I could then connect to via VNC and guide/complete the installation.
I would suggest asking the remote site to install a minimal (server) system with ssh enabled. You can then use YaST2 in text mode and zypper, etc.over ssh to install and configure the remote system, including VNC and anything else.
Our remote sites have live USB sticks preconfigured to enable basic work (connection to their organisation’s data services) and a reverse ssh tunnel to the support office. This permits remote repair or (re)installation with minimal local assistance. Most times they have lost the USB stick when they actually need it
Use a Gecko Linux image of OpenSUSE - install teamviewer on it and boot off of it. You will probably have to make the USB and install teamviewer for them.
Teamviewer will allow you to remotely install Gecko version of OpenSUSE. You can put an icon on the desktop and set a remote password for it.
They will have to boot the Gecko USB key and get the network connected (if Wifi) start Teamviewer. Since you know the ID and Password you can get in. I do this for my friends all over the world.