The fault doesn't lie in iMessage, it lies in Apple in general. Google's AOSP keyboard will IMMEDIATELY detect that you are writing a link when you'll put http(s):// in front of whatever else you're currently writing and will just shut up and let you finish without interrupting every 2 seconds with autocorrection suggestions. This does not happen on Apple's i(Pad/O)S keyboard, where typing a link will usually leave the user with an excercise in frustration, trying to fight over the autocorrection, which, for the 17th time, has decided to convert your URL into "normal words". Not even changing the keyboard seems to fix it, as, from what I remember, Gboard still uses Apple's prediction engine...