Leaks and overheating

[AJSingh]

Hey BMW enthusiasts. I am quite new to this community and recently bought my first car. It is a 2005 BMW 530i with the N52B30. Recently my car has overheated which I ended up taking to the mechanic, they topped up the coolant reservoir with some water and said its all good to go. The coolant at the time was half full. After a while I ran into the issue again during a spirited acceleration from 40 to 100. Took it to the mechanic, they pressure tested it and said nothing's wrong. Fan, thermostat and radiator are apparently working fine. What they have said to me now is that there is a couple of oil leaks. I've been told that the car had an oil leak from and due to the headgasket and a couple of seals have dried out. Upon doing my research, overheating can be caused by headgasket although not convinced at all that the headgasket has failed. I have been quoted $5k for replacement and around over $2k for a repair. I am in disbelief because firstly, N52s are not known for headgasket issues, secondly, $2k+ for repairs sounds absurd to me. I am looking for recommendations and people who've have similar issues in the past. I do feel the leak is from the valve cover gasket and not the headgasket. The coolant is not disappearing and the oil level has been the same for the past 3 months. Could it be old oil leaks? Is it really the headgasket? Is the overheating just a sensor failure? Any recommendations or suggestions are appreciated, I have included videos and pictures of the leaks and the engine bay. TIA.