Certified? By who?
"That said, Canonical's list of certified hardware is more constrained, featuring only a few vendors."
It's not just only a few vendors, it is likely a small subset of their models that have been certified. I tried finding a recent model desktop Dell with reasonable specs (64GB, 10thGen) and the list has no knowledge of that model, nor the whole set of models in that line.
And the list will have 3 and 4+ entries for one model number. It's like these are the records of successful tests on various individual machines. Perhaps self-reported somehow? And so "hit or miss" whether they've gotten 'round to your preferred model.
I'm afraid the list is no good for guiding purchase choices.