I will add to this thread by infusing a personal opinion. My first brand new car was my 2014 Passat TDI. I was not thinking about diesels, I just graduated from Pharmacy School, was doing my PGY1 residency, and my 21 year old beater 1993 Nissan Maxima that my mom's friend gifted to me for 7 years of pharmacy school was starting to break down far too often. My aunt was driving a 2012 manual Passat TDI and strongly recommended it for my first new car. I fell in love with it after test driving other competitor sedans. Got it for $33,500 in March 2014.
Fast forward to 2017, my mom hits deer and wrecks her Chevy sedan. She is now in the market for a new car. Thinking that I wanted something fresh, I decided to gift my Passat to my mom. It was the least I could do for her. Especially that i decided not to sell back my Passat. My aunt sold hers back. Now that I am IN LOVE with diesels, I search for diesels to replace my Passat. Noted a 2015 Passat TDI SEL available from dealer. Test drove, clearly needed new tires as the old ones were rough on I55 going 70mph. Offered 29k but dealer refused, wanting around 33k for it. I decided an old tech car was not worth same amount I paid for my brand new one. At that time, diesel market for non trucks was drying up. Options were SUV from Jaguar F Pace, Chevy Cruise, or BMW. I think Mercedes already retired diesels in the US. So I went to a BMW dealer and settled on a 2018 BMW 328d. In retrospect, should have special ordered 2018 535d, that is an awesome car and would have been better for now my growing family. That engine B57 was a single year newest BMW 6 cyl diesel in the US. So parts may become an issue vs 3 series 4 cylinder N47 that existed in US since 2012 over 6 years, plenty of parts going around. But anyways, I love my 2018 328d. It has a similar 4 cyl diesel engine to TDI, 45mpg mixed driving mileage (got to 50mpg on highway only trips). Kerma TDI tuned and drives like a champ. Unlike Passat, responsive and modern infotainment system, safety systems such as blind spot monitoring, convenience features such automatic wipers, head up display. Of course, I spent $10k more on a new BMW than what a fixed 2015 would have cost. But I do not regret this decision. BMW does not have stupid coolant degradation issues, no clogging heater cores, newer iteration HPFP with beefier roller to reduce failures, strong and reliable turbocharger, emissions compliant from the start. And later N47 engine models came with refreshed timing chain guides, eliminating timing belt woes that earlier EU engine models went through. Basically, once BMW introduced that engine in US for 3 series F30 chassis diesels, they already came with improved timing chain guides. My friend drives an older model of same F30 chassis, double mileage without same issues I deal with on Passat with half the miles. I feel BMW is indeed better made in many ways. Hence the price difference. It is not just being a snob, it really seems more reliable. The time will show as to which car will outlast the other. I service them both religiously.
So to make long story short, don't settle on a new Passat that is a dinosaur by age, the plastics and rubbers degrade with time. These cars like to be driven, sitting for 7 years is bad. I am sure there is a lot of corrosion, rubber is cracking and dry rotting, plastics are getting brittle. I doubt they sat in a clean dry garage for 7 years, likely outdoors in all weather conditions. Consider low mileage final year used 2018 BMW diesels. BMW retired diesels after 2018 MY. Want economy, go for 328d with 4cyl diesel. Want more room, consider 2018 535d or X5 SUV 35d. 5 series and X5 will come with 6 cylinder engine, so you will give up economy. My wife's X5 SUV xDrive 35d averages 32mpg. Not terrible for a giant bus of a car compared to my compact one. Lol. Good luck with your shopping decisions!