Can the efficiency mode downshift behaviour be applied to D mode? Tallinn is few hours drive for me.
It is of course possible, but I quit calibration in 2020, so I can not help you.
It can also be that it can be made softer, by lowering the gradient speeds and increasing/decreasing the overlap, as well as playing with the stall speed.
I don't know who has the knowledge and then wants to spend time to do this though. It can take a whole day
And because there are certain limitations and quirks with the gearbox (as well as sometimes it's mechanical condition), then it might be difficult to get the end result that makes the customer happy.
So from a commercial standpoint it makes very little sense for anyone to even attempt this job - those who could do it well usually have their hands full with stuff that is much easier and pays much better.
Your best bet is probably get really cosy with the gearbox, get a flash tool, buy a damos and start to study the funktionsrahmen. I doubt you will find anyone who wants to work on this with you, because most people don't know anything except upping the torque limiter and shift rpm.