Wait, do you even have a 3DS on hand? I have 2 O3DSes, a 2DS, and a N3DSXL (my main handheld) on hand. None of them have ever powered on unless there's a battery installed, even if it's dead. Though it's funny that you mention Android devices, bc my old tablet (Samsung Galaxy Tab A 8.0) kinda gave up the ghost a few days ago, by my own hand kinda.. It wasn't powering on, and it wasn't showing the little charging icon like it does when charging while powered off, (it was fully charged the day before, usually it'd show a "battery empty, plug me in you twat" message like you'd see on other devices) so I opened it up and unplugged the (non-removable) battery, which went well, but while I was plugging it back in to complete the re-seat.. the socket(?) snapped off of the motherboard. And I have no sodering equipment/skills. Though if I plug it into a USB charger, it DOES show that "charging while off" icon (thunder symbol in a circle, usually it'd then show a battery % and the circle would fill green to match) but then it just powers off, then loops. I CAN get it into the odin/download mode to flash a new firmware to it, but I haven't found any that'd let me get past the battery check. I mean, if I can get into the odin mode, and it DOES get power over USB, I think it's dumb that I can't get into twrp/recovery or even boot android.
Quick last second edit: sorry for rambling and being off topic, my bad