Fine to be disappointed with Vlad, but there was always a not insignificant chance that he would follow the development path of a typical highly touted prospect as opposed to dominating right away. It takes time to adjust to major league pitching.
Soto seems to be on a Mel Ott/Ted Williams trajectory as a young hitter and pretty clear that he's on another level compared to just about everyone, but Tatis, Acuna, and even Bo are outliers even amongst highly touted prospects in terms of adjusting right away and dominating. I still think Vlad could surpass them with the bat, but it might take time. We've seen flashes of it (had a higher wRC+ than Bo in August last year), it's just a matter of finding consistency.
As for his defense, he's played all of 20 games(?) at 1B. He's instinctually been conditioned to play 3B basically his entire career, so it's not a surprise that those exact instincts kicked in at a seemingly inopportune time. We're probably going to see more mistakes like this happen in the next 100 or so games, but you can only hope he starts showing improvement and doesn't allow it to happen at the worst possible time.