I’ve always considered that texting “hehe” is a light chuckle, a “heh heh” sound; “hehehe” is more of a giggle, whether coy or creepy; and any more “he”s than that delves into witchy cackling territory.
But “haha”, “hahaha”, and “hahahaha”, all “sound” the same to me and the meaning only varies in intensity but is more context dependent.
I think that typing “hehe” (or any of its variations) is like saying “gasp” or “shudder” out loud. Gonna take what you have to say a lot less seriously after that.