My solution was to have sleep trigger a script to set a timer that wakes the laptop up after 1 hour. The wakeup function then triggered a script that if it wok

My solution was to have sleep trigger a script to set a timer that wakes the laptop up after 1 hour. The wakeup function then triggered a script that if it woke up right at 1 hour after sleep, it would then hibernate (to disk), which could stay in that state indefinitely. Note, this was some years ago, I think SystemD has something like this built in, not sure.