There are probably a bunch of other machine candidates that feel this way to someone out there!
I know the exact sensation you describe here. But I can never decide whether it's a property of the thing itself, or where I was in my life when I stumbled onto it. My hunch is that it's mostly the latter: artifacts feel seminal when they hit as a formative time when we first gained a new capability.
I'll always have a fondness for the Apple IIe and the early Macintosh because those were what I had when I first started using computers to create. I'll always love late 90s electronica because that's when I fully discovered my love of music. My Lodge Dutch oven will hold a special place in my heart because I got it right when I was really learning how to cook.
That being said, I do think there is something special about that era of machines, even outside of our right-place/right-time nostalgia for them. I cut my early computing teeth first on a Timex 1000, later on a Commodore 128, and finally an Amiga.
The Timex was... ok. It was fun enough to pfaff about with, but so limited that it didn't really capture my attention in a special way. The Commodore? Amazing. It is responsible for my entire technical career trajectory. I loved exploring its edges. It was a powerful-enough system that Real Things™ could be done, yet still simple enough that the entire machine could live in your head, so to speak. The Amiga? It was amazing, but it was almost too much. I couldn't hold the whole machine in my mind any more, and had to rely of greater level of abstractions to get things done. What was doable was incredible, but there was an undeniable sense of loss, too. At least for me.
Some designs are made by passionate talented people pushing the limits of their own skills and imaginations to explore what might be possible.
And others are made by mediocre people throwing some some minimal-cost low-effort derivative crap together to make as much money as possible.
One is an inspiration. The other is kind of offensive.
I suspect a lot of computer nostalgia is really about chasing that first feeling. I also suspect that's a lost cause, because you can't find the limits of imagination on the trailing edge.
Of course you can get echoes of it. Which is almost reassuring - but I really wish there were more high-skill high-imagination projects in computing today.
But, I've read a lot over the years about computers from then and have spent a lot of time on modern computers.
The Amiga, from what I can tell, was actually special, not just from a nostalgia sense.
They seemed to push the boundaries of computing at the time, gave a glimpse of what could be but were stuck in that inbetween phase and just couldn't quite make it.
I think they deserve all the praise they get. They seem like they were one hell of a machine for the time and despite the huge diversity of things like linux distros and such these days, things like the RPi and various comparable devices, a huge range of consoles, phones and other arm based things, there really isn't anything like the old days of computers where everything was different and devices were made to be tinkered with.
Not to say everything about that era sounded awesome or better or whatever, but something does seem to have been lost that machines like the Amiga seem to embody.
I will keep looking, but breaking up the thing that was in one way or the other part of my life for >25 years felt very strange. So many memories. So many firsts. And I believe that this is a big part of that feeling of specialness such things have.
A new laptop doesn't provide any firsts for me. Nothing new. Maybe faster. Maybe a better keyboard. But nothing new.
PCI SCSI controllers are around and fairly cheap, looks like there are even some PCIe ones out there (not as cheap). I've never gotten as far as the software side of it though. I imagine one might create an image of the disk, and use it with Mini vMac, but I think I still need to figure out the SCSI setup. (I have a PCI SCSI card that I was attempting to use to interface with some tape drives-- different story.)