zypper -vvv ref will download files through Internet to refresh patches list before the upgrade of system, can I get copy this files from other computer to refresh patches list on my second computer?
Files downloaded from repositories are in /var/cache/zypp/raw, so theoretically it should be enough to copy them. But I am not sure at which point zypper will generate the actual metadata it is using (in /var/cache/zypp/solv) - any time it detects they are obsolete or only when refreshing repositories. There are also corner cases like signing key updates.
Test and tell us 
You should build, maintain and distribute your own YUM repository. Have a look to part c):
Translate german to english with a translator like deepl.com.
Create your own YUM repository on your reference machine. The reference machine needs internet access. Download all neccesary software packets (*.rpm) from the official (open-)SUSE repositories and copy them to our own YUM repository.
Distribute/mirroring your own YUM repository with rsync (over ssh) from your reference machine (master) to all your (open-)SUSE machines (slaves). Slaves machines have only access to your own repository. Only the master machine has access to the offical repositories.
You need the experience of an advanced linux administrator for this task.
NOT worth the effort for two machines using Leap 15.6 … the updates over time are minimal, so not worth the extra effort.
But if using TW and only update once a month, THAT’S a different scenario.