My wife got me this Hongdian 1851 for Christmas last year, along with the astronaut pen holder. Since I keep it out on my desk, it is the pen that I reach for most often. It has the finest line of all of my pens and I keep it inked up with iroshizuku murasaki-shikibu, which is an incredibly close match to the body of the pen. It has a lot of feedback without being scratchy, and is great to write with.
The calculator is a Casio fx-260 Solar II, which Kristi also got me for Christmas some years ago. It’s the calculator that I grab most often since it is the easiest to get to. It’s my little Apocalypse Calculator since it has no battery and is solar powered only.
I’m not sure about a European distributor, but I can tell you that mine, from Amazon, has a nib that looks like the one that you’ve found on Aliexpress. I don’t know if there’s a difference between them. The Forest Rainbow that I have has an anodized nib that probably started off all silver, but both of them are extremely fine, and wrote beautifully right out of the box.