@mgiammarco See https://ranchermanager.docs.rancher.com/integrations-in-rancher/logging/logging-helm-chart-options#additional-logging-sources
But if you want the current system log you can run journalctl --file /var/log/journal/$(cat /etc/machine-id)/system.journal > host_system_log.txt and tar that up, or can see them all in the directory via ls -lat /var/log/journal/$(cat /etc/machine-id)/ latest to oldest order. You could then use the above command replacing system.journal with system@lots_of-numbers.journal for a specific date. Then create a tarball as required…