How to do a factory reset

first off all i want to thank the umbrell team for their excellent work.

my question from a newbie,

i had some issue’s with my node and i want to do a completly factory reset.
i cant do it with ssh. it wont recognice my password anymore. i have flashed the sd card, but when i want to login i see no confetti to set up a fresh new umbrell. how can i fix this problem.