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Presoldered split keyboard
(self.mechanicalkeyboards)
Are you addicted to the clicking sounds of your beautiful and impressive mechanical keyboard?
If so, this community is for you!
Here you can discuss everything about mechanical keyboards (and only mechanical keyboards).
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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%.