Of course X belongs on the 53. Of course he's better than Tutu and with more potential (just from size alone). Tutu is straight line fast. And he is not very strong. Just look at him! You don't have to be a trainer to see how slight he is.
But there is far more to "speed" than measured 40 times. Any Rams fan ought to get that by now re: Kupp and Nacua. Heck, Jerry Rice was a 4.6 guy. It is how fast you play in helmet, pads and cleats. Slow Kupp and Nacua catch the ball and run away from people. Does fast Tutu? Not that I've seen.
Tutu may have his place on an NFL team. But the Rams just have too many better overall players at WR than to hang on to him. Let him go somewhere where perhaps they can scheme him open and use him in a different offense than the Rams use.