yes, I use a wall PSU from Pure DAB radio 
DMM shows something like 12V, but it’s still within 5-24V bracket
I’ll give Tasmota or this one a go because it’s just a relay and should be easier than PIRs (like this story)
Oh no! If it’s a defective unit, I’l have to film a video (!) showing that it’s defective - bought it from Banggood, and they stupid policies on reporting problems drive me crazy… :
Have no idea how to convince them