The problem is the opposite, he can't seem to control overboost.
The logs are inconclusive on this, because WGDC is 40-70% in all of them.
In the first logs the throttle was shut. If the throttle is shut obviously you are going to have huge pre-throttle pressure.
As I said - first step is to kill WGDC in a such case by setting CWMDAPP to 16 and LDRAPP to 0.
If it doesn't overboost after that, then it's a question of linearizing the boost control from scratch.
My posts and others tools derived from my posts exist on this very forum to make this process as simple as possible.
Of course on S3 there is base boost to kill first, as plsolr is not what it is and so on.
Tuning ME7 on any turbo is a very straightforward job, but you need to be very strong on the basics and understand what you are doing.
If you don't know what KFMIOP is or what a PID is, there is little hope.
In this day all the materials are available online. There are countless tools that make life easier and so on.
But you still need to understand engine mechanics, control systems.
This ecu is from 1997. Try tuning a big turbo 4.0TT...