I've owned all the systems being discussed - RB/RZ67, Pentax 67, Hasselblad 500CM, and I currently have access to a Fuji GX680. All of the bigger negative cameras are beasts. I'm currently shooting a Pentax 67 - I love it for the ease of hand-holding (if you get one, do NOT skip the wood hand grip - it is essential, IMO), and the range of lenses that are generally speaking much more affordable than their counterparts in those other systems. I currently have the 35 Fisheye, 45, 55, 75, 90, 105, 120 Soft Focus, 135 macro, 165, and the 400 f4 with 2x extender. Back in my Hasselblad days I had just the Superwide, 50, 80, and 120 lenses. And I probably spent more on the three (50,80,120) than I have on the total Pentax glass kit I have.
My one big gripe with the Pentax is that it has certain features that are not terribly robust (notably the meter chain and the film advance - I have four bodies, one of which has a broken meter chain which I don't care about because I don't use the meter prism, and the other three have broken film advance mechanisms). My most reliable and robust camera was the RB 67, followed by the Hasselblad. I had a bad run of luck with the RZ - I had two RZ bodies both of which had multiple repeated failures.
The thing about Hasselblads is that if you don't use them regularly, they will start to fail (and fail very expensively) due to lack of use. I had a 500C body that I put up on a shelf because I had gotten a 500CM with the acute-matte screen. The air bladder mechanism that regulates the rear doors of the body failed and that was a $400 repair back in 1996.
The glass on all of them is not an issue - you can say that Hasselblad glass is sharper/more contrasty, and you're probably right. But honestly, I've never been disappointed by the images I've shot with any of them, and the only way you could tell which camera shot which is aspect ratio ruling in/out the Hasselblad.
Since you are considering square format, I'm going to toss another contender into the ring that nobody else has mentioned.
Rolleiflex.
I know there are no interchangeable lens Rollei TLRs. You've got three options - standard Rolleiflex, RolleiWide, and TeleRollei. I have a pair of standard Rolleis and a Tele. After being serviced, they have been the most reliable cameras I've ever had, despite being 70+years old. There is an advantage to having one and only one lens option - it makes you think about the image in front of you rather than "what if...". They're also light (relatively speaking) and compact, and when you want to shoot on the street, they're really good at stealth because they have no mirror slap and the leaf shutter on them is at least as quiet as a Leica 35mm. Using the waist-level finder also means you can literally shoot from the hip and people won't realize you're photographing them.
The first time I traveled with my Rollei, I had a lot of anxiety about if it would be too limiting. I took it to Paris, shot on the street, in museums, at night, on a tripod and handheld. I ended up with some of the best photos of my life. The Rolleis have since been with me to Rome and Florence, Mexico City, Toronto, and New York City, as well as extensive use here at home.
Don't feel the standard 80mm limits you for portraiture - there have been plenty of world-famous portrait photos taken with a standard Rollei. If you get a vintage Tele Rollei, you'll want to invest in a Rolleinar closeup lens kit for it as the minimum focus on the Tele is almost 3 meters without the closeup lens. There is a modern Rollei 4.0FT version that will focus down to 1.5-ish meters without the closeup adapter, but those are selling (when you can find them) for well over your stated budget.
