“Crucial to our disagreement” is 8 syllables to “cruxy”’s 2.
“Dispositive” is quite American, but has a more similar meaning to “cruxy” than plain “crucial”. “Conclusive” or “decisive” are also in the neighbourhood, though these are both feel like they’re about something more objective and less about what decides the issue relative to the speaker’s map.
“Crucial to our disagreement” is 8 syllables to “cruxy”’s 2.
“Dispositive” is quite American, but has a more similar meaning to “cruxy” than plain “crucial”. “Conclusive” or “decisive” are also in the neighbourhood, though these are both feel like they’re about something more objective and less about what decides the issue relative to the speaker’s map.