No it’s not. The Passat has a huge boot and importantly the back window is quite upright so you get the full height across the whole boot. The BMW not only has a shorter (front-back) boot but also has a steeply sloping window making it significantly less voluminous.
We have two large-ish dogs and were in a similar car-buying dilemma a few years back, all of the BMW & Audi estates have surprisingly small boots with no headroom. We ended up with a ’56 Passat. The alternative, perhaps surprisingly, was a Focus. That has an incredibly big boot for what is a smaller car.
Our Passat had a few teeting problems when we bought it but since then has been great. Electric handbrake was one of them. £200 for an exchange caliper, easy DIY fitment and despite what anyone tells you, you DO NOT need to go to a dealer to reprogram the car afterwards. Electric steering lock was another, a PITA but can be fixed for free if you don’t mind some spannering. I think the only other thing was the boot handle acted up and needed a new unit. Not too bad.
FWIW I’m generally a BMW fanboi, I’ve had about fifteen of them over the years but I’m utterly convinced that BMW’s build quality took a nose dive around 2000 and hasn’t really come back again. My daily is a 2001 320td with 157k miles on it and it’s been great. I had a 2003 530i that was a total lemon. My brother ran a 2008 335i for a while, lovely car, but absolutely appalling reliability, constantly going back for warranty work. It actually put him off cars ! He now has a ’54 Golf GT and is chuffed to bits with how hassle-free it is.
I don’t like VW handling though. The front always feels too soft to me.