"Binary" headset adjustment, meaning going directly from loose to jammed, without.passing through being stiff is almost exclusive caused by incorrect stack sequence.
Pull the stem, put your brain into analytics mode and confirm the correct assembly. It might help to find an exploded view and compare.
When I'm in doubt, I assemble only up to the headset top cover and load with direct finger pressure to see if I'm feeling a bearing or dry metal contact.
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