Missing Feature in the Varia RCT715 Radar: Battery Saving and Signaling

I ride a trekking bike equipped with its own B&M lighting, powered by a bicycle dynamo located in the front wheel hub. Additionally, I use a Varia RCT715 radar. However, this radar lacks an option where the lights are completely off and only turn on during the detection and approach of vehicles from behind. I don't want to give up the high-quality lighting on my touring-city bike.

The Varia RCT715 has the option to turn the lights on and off, but it lacks an option where the lights are off, and the light signal activates only when a vehicle approaches from behind.

In my opinion, such a solution would bring several benefits. Firstly, battery savings without duplicating the rear lights of the bicycle, which we don't want to give up. Secondly, it would expand the customer base of those riding trekking and city bikes, which already have high-quality lighting with a standstill function. Additionally, the radar would draw the attention of other drivers approaching from behind. Competing brand radars have this option, and it works excellently. Especially since the Varia RCT715 radar, once charged, works for a very short time, only a few hours, and charging takes up to a dozen hours, despite assurances in the user manual that it takes four hours or two times four hours.