If you are a talented professional who takes terabytes of unique & engaging photos, disregard- but otherwise, as another photographer, let me suggest you focus on culling instead of storage.
(Photo Mechanic was a godsend for culling; it's fast as blazes even on weak hardware, and cheaper than a new processor or more DRAM)
Even among talented professionals, you are lucky if your "hit" rate creeps over 10-20%, especially outside of controlled studio lighting. I've always felt the amateur dream of "taking better pictures first time" ignores the reality that many pros have long shot in bulk and culled too.
I'd argue that the extremely un-glamorous secret to better photography for _most_ of us once a few basic composition rules like rule of thirds/golden ratio etc are understood is frankly to take many more photos, and yup, cull, cull, cull. This is precisely why tools like Adobe Lightroom come out of the box with such a heavy focus on keyboard shortcut support for zipping through an import and marking the winning images in a quick pass.
p.s. I know DarkTable doesn't want to be a file manager, but it really needs to have Delete for this very use case.
Or a good AI to help you categorize the pictures and look for features you may have not noticed.
But I wish it had a setting to clear out the ones that it's most confident are bad. If it's dark or I'm moving, there's a fair chance the picture will be blurry, so I (and everyone else) just take a few. Recognize that and let me cull automatically, please!
I'm sure it will also gain more ability to cull - I mean it already picks out things that looks like documents (e.g. from using the camera instead of a scanner), and offers to archive them for you. I'm sure they'll add more categorization as they gain sufficient confidence.