Will be good to inform your peers about the situation, being offline.
If they understand the situation will not force close the channels and wait.
If you do not have their contact, you can post your “maintenance” on Amboss Billboard (also you can check there if they have some contact details - see their node page).
But anyway, a channel can stay offline as long as the peer want to keep it like that. So is not a big deal, from LN perspective.
My opinion… just close cooperatively your channels, withdraw the funds into a secured wallet and wipe that node, keep the hardware for later when things start calm down.