I’ve been low-key fighting with my crawlspace dehumidifier’s sump pump trying to get it to self-siphon once the motor stops to keep draining the rest of the sump and mostly further clear the line. I finally did it!
FWIW there wasn’t a lot of vertical space to work with and the horizontal distance was over 20ft.
Yes, we need to see! It’s not like I might build on off your solution. Just asking for a friend.