This is a neat little module that I just ordered. https://www.aliexpress.us/item/3256804112798600.html
Hooks into bafang BBS* display wiring to pull proper power for head/tail lights, but also use the existing crappy 6V/.5A headlight wire to allow turning lights on/off via bafang display.
I'm gonna see if I can wire up my existing older dynamo headlight (B&M Luxos B). I also have a B&M toplight rear light, but I'm guessing I'd be better off with a general ebike rear light w/ separate brake light wire. #BikeNerdStuff