Then just switch off the radar based regen. With that you have achieved exactly that. You can do this in the settings of the on-board computer.
You want the eco mode because you expect more range from it? Then I would take a closer look at the topic in the FAQ, normally the eco mode doesn't do that much.
If none of that prevents you from wanting to make this setting, then you unfortunately only have the option of having to recode the car. Unfortunately, this is a bit more time-consuming. I describe how to do it below. Using this program is at your own risk:
First of all you need the dt4all application. In the second window you then press "BCM", in the third window you then scroll to "Fal MMI" and open the options by double-clicking. Scroll down to "ECOMODE_PREVIOUS_RESTART_CF" and start the expert mode by clicking on the Albert Einstein symbol. on the left you set it to "true" and on the right to "false". Finally save the setting with "save".
If the setting is not accepted immediately, unplug the car, lock it and wait 15 minutes.