Me7 can deviate over time and cause flare up if there are issues , boost leak ect . These K04 hybrids are very temperamental to tune and you really have to tune them in a totally different way you tune a std car
Remember , ME7 doesn't request boost , it request torque , aka airmass . turbo control maps are only really a character on how the turbo responds.
Try this , put your n75 back on . With vcds , go to engine 01 and in adaptions , put in 000
and press save , in basic settings , go to 98 and do a throttle calibration.
You might find the car will drive good again , for a while anyway