I really hate seeing these stolen bike threads and they are way too frequent.
We all feel your pain Beezerk

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And bike thievery won't get any better in the future. Here in the U.S. a bike thief knows at most he gets a slap on the wrist from our liberal ass judges who let the perps walk out the same day, even if they are caught and arrested.
Sadly, you could also be sitting at a traffic stop on the way to a trail or in the trail parking lot and someone can walk up to you and pull a knife or gun out and simply "take your bike" (I do have a canister of pepper spray on the handlebar but it's illegal in many countries or cities I'm told). But It's really not worth an injury or worse our lives to try and fight them off.
Of course we all know, the best thing to do is lock it up even if as you said you only took your eyes off it briefly. Get some type of insurance on your next bike. I pay $135 a year on a $6,700 ebike with replacement insurance. These Ebikes drop like a rock in value, so having an insurance company only give you 1/2 it's value would suck.
Lastly, we all like an ebike with bling and as you described yours the fancier the look, the more of a target it becomes. Mines black. I would have loved to get one in red or purple, but I know since I'm in a decent sized city it would not last long. Groups of thieves can follow you with a van and grab your bike at any time. Your only defense is getting insurance. I use a hidden Apple Airtag too, but I'm not about search it out myself if it's stolen and from waht I read in the threads most police won't bother to search for it either. I rent and even have a new Bing camera trained on it in my basement which sends an alerts to iphone and watch if anyone even walks near it.
Bike and accessory manufacturers don't care about protecting your bike either. I have the Bosch Nyon on it. When I remove it the motor is incapacited. But it does not lock the motor so a thief can sill ride away with it. Without locking the motor make it a useless feature. If the pedals were locked a thief would have a tough time trying to run with a 60 lb ebike. Bosche only cares about the $450 I paid them for the Nyon!
One sad story I read here or somewhere else was two ebikers parked in a lot drinking coffee in their van with their ebikes leaning up against the van and someone swiped one or both bikes while they were sitting there in the van!