Umbrel startup sequence [what happens behind the scene]?

After a weather-related power outage, when my power is restored, my umbrel becomes unreachable. It can be fixed, but I want to find out why. what can be the cause?

1/ I am normally using a wifi only as my connectivity. A regular file called wpa_supplicant.conf was created and is used, and pi’s wifi interface mac address is set up in my router to get same IP every time. After powerdown-powerup, that IP becomes unreachable.

2/ in case of a power outage, and return, pi becomes unreachable. I can’t ping it, can’t ssh to it, and umbrel.local is not on.

3/ if I unplug it, get it to the router with an ethernet cable, power it on, and provide my password, umbrel starts, synchronizes and works. it becomes reachable from outside via tor. As expected. I dont like shutting it down by puling the power cord…

4/ if i turn it off, (shutdown, not kicking out power) and move it back to it’s station, turn it on with wifi only, everything works.

5/ I don’t recall testing if it comes back on in case of rebooted wifi router/cable modem…anyone tried?

So what exactly happens during boot and umbrel startup and why it doesn’t come back online after power loss? How does it detect connectivity, wait for lost connectivity, restores wifi/ethernet, etc? Who knows this? Where is it documented?