PoE Splitter 12W, 48V to 12V 1A Gigabit IEEE 802.3af Compliant PoE Adapter with 6kV Surge Protection, Power over Ethernet Splitter for Security IP Camera, Non-PoE Devices 12W 5.5x2.1mm DC Plug Gigabit

It sounds like a hack. The supported way would be to use a poe injector and on the other end, if the device does not support poe, a poe splitter.Something like this https://www.amazon.com/Splitter-Compliant-Protection-Ethernet-5-5x2-1mm/dp/B0GYT8MPBPI even have one with adjustable voltage and multiple barrel connectors.There are some with usb power output. So it may well work but will be difficult to maintain by someone else i would think.