Seat Ibiza ST 1.4 TDI 2015 – Constant emergency run, no one finds the error

Hello together, I hope someone can help me, because I am really in despair. My Seat Ibiza ST 1.4 TDI (2015) has been standing in various workshops since November – so far without a solution. Problem: First: Emergency run with constant drive (1800-2000 rpm) with error message “load pressure limit exceeded”. After restart the car drives normal again. Now: Emergency run already when accelerating (>2000 rpm) with error message “load pressure limit below”. completely removed, vacuum box on the turbo no longer moved. Previously made: ? All relevant sensors changed (LMM, charging pressure sensor, temperature sensor, sensors before/after charging air cooler) ? Cable checked – no abnormalities ? vacuum box on the turbocharger tested – works normal, does not act ? Turbocharger and vacuum box replaced – problem persists! ? AGR valve cleaned ? DPF checked – is free Directly after the installation of the new turbo: first ride – again emergency run. It feels Ask the experts: What else could that be? Has anyone ever had such a problem? I am a student, I drive 80 km a day and can’t afford a new car. For me, this is an economic total damage, but I want to know what the cause is. I hope for your help! Thank you in advance! ??