@洪 民憙 (Hong Minhee) :nonbinary: I remember someone citing studies specifically for Chinese (I think it was on a YouTube channel called Julesey, but I'm not sure exactly), and admittedly didn't check her sources.
And it isn't only Latin scripts that use spaces, I mean, Korean does, Cyrillic does, just like modern Arabic.
But you are right, not having spaces isn't what makes it hard for me to read Chinese, it is the existence of 100s of characters :)