Well, my head is spinning, but I've made a bit of progress. I thought I'd start by trying out a few of the ones you and others have characterized as user-friendly as well as one of the more bare-bones ones.
The (hopelessly unscientific) test plan was:
Challenge 1 - write live system ISO to USB drive and boot it on my 2015 MacBook Air (which, though old, still counts as exotic, I guess.)
Challenge 2 - make sure display, network, trackpad and keyboard (+ intl. layout) work correctly. Be able to SFTP to my Mac
Challenge 3 - with little to no docs reading (how is the package manager invoked from CLI?), use the terminal to set up the right environment for a couple of relatively portable hobby projects I've been recently working on (on Mac), compile and test them. This includes, among other things, installing clang or g++, SDL2, Wine (to run an ancient ARM assembler) and finding a usable GBA emulator.
Limitations:
A: 8GB RAM. More ambitious stuff (KVM macOS, VisualStudio Code) will have to wait for an actual install.
B: Deliberately avoiding exposure to the docs is silly but I thought
such an approach would give me an indication as to whether
there exists a distro that uhm, "thinks like me".
Candidates:
Ubuntu, Mint, Fedora, KDE Neon (which, if I'm not wrong, is Ubuntu LTS preconfigured as the latest KDE) and Void.
Results:
Challenge 1: unremarkable. All worked right off the bat except for Void, which made it as far as showing the mouse pointer but then froze.
Challenge 2: well, boring ;) All distros were pretty much ready to use and required minimal tweaking. With the tweaking part ranging from effortless (Mint) to minor headscratching (Neon). Not sure whether /etc/X11/XF86Config still exists but I did not miss editing it today.
Challange 3: more interesting:
Neon: all worked as expected except some trial and error required to get Wine working: wine32 was required but it wasn't getting installed by default, apparently. (Not a whole lot easier on Mac anyway, with separate downloads & installs for Wine and XQuartz)
Ubuntu: I failed as apt refused to acknowledge the existence of the packages I needed. This is weird as I believe Neon relies on the same package database. Though undoubtedly my fault, not reading the manual, it is perhaps a bit interesting that I could not readily find my way around the problem.
Fedora: everything worked except for Wine, as the live system ran out memory (disk space) on installing it. Not a big deal, everything else worked very well. Aside: I'm an avid runner and "DNF" is not the most likeable of names for a program I have to use very frequently! j/k..
Mint: everything worked at take one.
I know this isn't even scratching the surface of the surface but I think for now I'm going to go ahead and play more with Mint and Fedora after installing them on MB Air hardware or MB Pro VMware.... with a mind of getting back to KDE/Neon eventually.