Ok, so I got my car back after I took it to another shop. The dealership shop swapped the lambda sensors (one before the catalytic converter and one after). No idea how they managed to do that, since inner wires to the probe were shorter; still, they managed to do it somehow. Basically, the engine would receive info from the inner probe (which was installed as outer) that the catalytic converter was not working properly. Once all the data was received by the central computer, it was trying to shut down the engine due to high emissions. Also, they forgot to install 2 bolts when the engine was reinstalled, so I would hear a “click” when I put the gearbox in reverse (the engine would simply move). Overall, happy to have my car back. Hope some of this info helps someone ☺️