Oil leak issues with 2016 Passat 1.8L

I am having issues with my mother's vehicle, a 2016 Passat with 1.8L engine. It's got 177k km on it (just over ~100k mi) and has been having issues with a persistent oil leak since sometime in the spring last year.

The engine was stuttering and stalling, and dealership determined that there was an issue with cam position sensor that had caused damage and needed to have camshaft replaced under warranty. The service took some time while parts were on backorder, eventually it was completed but ever since there's been a slight oil leak. Oil level sensor would throw up a warning and it would be at the bottom of the dipstick around every month and a half or so. Just recently over the past few weeks this leak seems to have gotten much worse. I had to top it up two weeks ago, and then just this morning it was so low it wasn't on the dipstick and took just about a full quart, this was after it had been driven ~3 hours yesterday and been fine the whole trip, implying that the leak was so bad it went from just above warning level to off the dipstick in 24 hours.

I went to top it off while the car was running this morning, and after I pulled the fill cap it was loosely in my fingers and there was so much vacuum in the valve cover that it pulled the cap out of my hands. As I pried it up again I felt there was indeed a massive vacuum and it almost sounded like a shop vac. There was a slight bit of brown milkshake on the bottom of the cap, but the oil on the dipstick looked and smelled fine, nothing too concerning with it.

I'm not sure if this is normal on this engine, I can't imagine a reason why there would be so much negative pressure under the valve cover and I can't imagine what would be causing it if it was an issue. I've tried looking at where the oil is coming out from both the top and bottom without taking the plastic skid plate off but didn't find much to speak of.

Is this a common problem or known issue? The vehicle has been serviced regularly and never had any other issues. Is there something I should take a look at?

Thanks in advance for your time taking a look at my post and please feel free to ask if there may be more information that could help.