Home Assistant OS – offline access via direct Ethernet connection to laptop not working

Hello, I plan to use a raspberry with HAOS as a standalone for my faraway installation. It should work for automation and monitor the data.
The setup is only powered by the sun and 12V battery.
Therefore I have no network available at the site.

How can I access directly to the HA frontend, to setup the automation or download the monitored data?

Thanks for your help!