I suspect there's a strong bias in vowelCount % 2. A quick look at English 100 most common [1] has 1's at 73% and 0's at 27%. That would even out with longer words but I wonder how much. Maybe there's something else that's just as easy with less bias?

[1]https://www.englishclub.com/vocabulary/common-words-100.htm

Hm. That makes this puzzle all the more interesting. Maybe it's because I made a Wordle solver app recently, but word statistics are on my mind.