The lights most likely do not have the extra circuitry to talk to the charger to negotiate voltages. Since it’s a charger that can change voltage as you stated then the device must be able to say “hey give me 5v”. You will need to use a dumber 5v only charger for those devices.

Sounds like a job for Big Clive. Although idk how to contact him. Maybe you would need to join his Paterion.