It wasn't clear that it was a 13 second deal before going low. It read as if it was 3 seconds until it went low, adding to the 10 in software. You need a resistor on the output to discharge the cap faster. It will mean more current dissipation when operating, though.Since this will be a voice controlled device, as soon as i say "Hey google, turn off device" the powerplug turns off and the 13 second countdown until the cap is dissipated until digital input turns LOW. I cant see a way to anticipate that in software.
Well as my name suggests im a noob, haha... I have used arduinos in the past, but only at a beginner level... 555 timers dont seem as intuitive as working with an arduino where i can control timing more easily. The 10 seconds delay i have implemented is just a placeholder until i know just how long my "actuator" takes to travel the desired distance.