V6 TDI – Engine damage at 150,000 km plausible?

Hello to all, 3 days ago suddenly on the highway at 180 km/h strong jerking in the engine and no more power in my V6 TDI. Before never encountered problems with the engine. Immediately stopped and tow to the next VW car dealership. However no error indication and also at the following reading in the car dealership no messages in the error memory. Today call from the car dealership: 2 spark plugs have broken off and parts of it fell into the engine. Engine was probably hard besc Compression in cylinders equal to 0. Further statements are possible only after the cylinder head has been removed, which should cost only up to 23 working hours and 3500,- Euro. Probably a replacement motor is then needed. Now I ask myself, of course, whether this is realistic. I don’t know the car dealership and I have never been a customer there. I’m a bit perplexed at the moment as something like this can happen with a Phaeton V6 TDI. Especially since I regularly inspect a VW Autoh The vehicle was never heated or even kicked to the stop, but always treated carefully. Now I am thinking about whether the investment in an exchange engine at my MJ 96 is still worth it at all. Sure it is a beautiful vehicle but the replacement engine will probably exceed the market value significantly. If anyone still has an idea that I don’t think of right now, I am happy about the feedback En. Greetings capdoc