In the Guides section of this forum, is posted Getting started Umbrel guide with a special section (to remember) about making backups of you Umbrel LN channels.
That file you can save it wherever you want.
You can do your own rsync script if you want to save it in a separate USB memory attached to your node.
Here also you have a guide about 7 ways to restore your crashed node (I hope you will not need it)