I think you must have misunderstood the concept. I did not use a ethernet splitter and extra cable mess...
I use my router as IP supplier, 1 ethernet cable to my RPI, so I have cable to my domoticz, the RPI gets IP via cable, and if the I'm not able to ping gateway (router) then there is no power as the gateway is down.
the ONLY extra thing I have purchased is a the powerbank
Indeed I misunderstood, it makes much more sense like that
Perhaps French, German and Dutch supplies are more reliable, but here in Romania, "Vorsprung durch fuckup" prevails
Same here in Vietnam... That's why I'll also have a wifi gateway with battery backup soon.