I have read the whole thread, and i can tell you to 99,99% that mapping is faulty.
Overboosting like shown on the video s typical for exceeding MAP sensor reading levels.
The car then generates overboost which is not seen by MAP sensor anymore.
This has nothing to do with wrong turbo, because boost level is always controlled via ECU, WHEN the mapping is done correct.
Your MAP sensor can read exactly 2983mbar absolut, all whats exceeding this level is UNCONTROLLED boost.
If a requested boost level from 1,9bar is programmed, you have not even a 100mbar space to the limit of the sensor.
So if your mapping makes boost spikes, it immedeatly gets into uncontrolled levels.
You can solve this in 2 ways.
Get a remapper who is capable to write your software which doesnt spike out (pre control mapping) and maybe think of a little lower level, like 1,8 bar so that you have at least 183mbar left until the sensor reading exceeds.
Or:
Get a MAP Sensor which is able to control your desired boost levels.
Anyway you need a chiptuner who really is into mapping all over, not only bending around on some mapping parts which look like they could generate power....
Greets, Alex