16
Presoldered split keyboard
(lemmy.sdf.org)
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The Iris Rev 8 might be just what you're looking for. In any case, I think the term you're looking for is "hotswapable" since you want DIY without soldering.
Personally, I have the Ergodox EZ and I love it. It almost meets all of your requirements but I think it's more than 40%.