In this picture you have two maps installed into your home compter. CNE NTU 2020.1 and CNE NTU 2020.2
CNE NTU 202.2 is the map you have installed on your device.
I will have a modest bet with myself that the German route was created in 2020.1 which will (possibly) result in some recalculation when the route goes from your PC into your device and then into Trip Planner. That in itself should not account for a delay of eight or 10 minutes.
Delete map CNE NTU 2020.1 from your home computer and empty the trash can, you do not need it any more. Then recalcualte the route afresh in CNE NTU 2020.2 on your computer and drag it into your device. Does that speed things up?
To be honest, as I can install and run your route on my Nav V, the problem (logically at least) can only lie with your Nav V, not elsewhere. Have you changed the SD to a new fresh one yet? I think we are bulding up to hard reset time, reluctant as I am to recommend that course of action.