I went from my 2009 maxxed-out MacPro to a MacStudio a year ago. Had a couple of SSDs under the hood and several JBOD boxes hooked up to it. I wanted to modernize and de-clutter the MacStudio.
My solution was a to start with 2TB under the hood so that I had plenty of room to work near-term projects without running out of space. I added a 4TB Samsung T7 for nearby storage then a 2.5 inch 5TB Segate for my TimeMachine backup.
But that only solved my current projects.
For my archives, I bought an OWC 4-bay enclosure that I think is Thunderbolt or at least some kind of faster USB-C. I added a couple of large drives (14 TB & 16 TB, I think), plus a smaller drive that i mirror my last two years files that gets stashed away when I'm absent. I have another 8TB drive with older work back to the 1990s that I fire-up when I need to dig deeply, otherwise, it's usually off.
On the two large drives are my archives back a decade. For most of my files, I now have 3-4 copies, mostly placed in another building so it's not perfect but it's better than most.
My approach dates back to way before Lightroom and works for me. Key is using Photo Mechanic which dove-tails into the Spotlight search engine, part of the Mac OS.
I think you approach using a larger SSD plus a JBOD (which also allows RAID, both striped and mirroring) may be an affordable soltuion to your new system. The larger drives I have are fairly affordable, very reliable and probably bigger capacity than when I started building my new system.
Though I'd love to have all SSD storage, it's too expensive and overall can be less reliable than HDD storage, but my system works fine for me.
