Let's Control It

Hello to everyone
My name is Fred, I am French with basic English abilities so sorry if sometimes I write strange sentences.
I am not new in the domotic field, I am running a Rpi with domoticz and a RFlink for several years now but it died a week ago.
So I need to fix it or rebuild a new one and I have plenty of questions.

Have you figured out the problem? Have you tested the Raspberry Pi separately? While Raspberry Pis come with a TVS (transient-voltage-suppression) diode ( https://partstack.com/c/diodes/transien ... on-devices) to provide some protection against voltage surges, only certain models feature a resettable polyfuse to handle overcurrent—the Pi 4 and Pi Zero lack this feature. Next time consider the following issues like overcurrent, liquid spilling reverse polarity etc. https://www.makeuseof.com/raspberry-pi-ways-to-kill/