Tüv is Tüv?

Good day, everyone, we have just bought a used B W124 e220, Bj 1995, (3100.- Euro). Tüv until 01.2025. After the purchase a car expert who lives in the neighborhood took a look at it, He said the Tüv had not been allowed to release the car so in no case: wheel box at the front left rusted through, not insulated cables in the engine compartment. Now, 3 weeks after the purchase, the automatic transmission makes difficulties. I now ask myself whether the seller da noc Is it possible for me to carry out a major voluntary investigation at the Tüv, where the previous HU was flawed or “funny”? We would be happy if someone could report on similar experiences. With best thanks and greetings Marc