That's definitely the swing skill for Walsh. If he can't at least be decent on open 3's, especially corner 3's, he'll struggle to find a spot on an NBA roster.
But mechanically it's not broken like Andre Jackson Jr's shot. His base may be too narrow and he often lands split legged which tells me he's not consistently squaring up. I think with work he can be respectable off the catch. Which is important because he doesn't have any real bag off the dribble either.
But he's athletic and a good defender with a high motor and great measurables. Part of why I'm high on him is the idea of stashing him in the GLeague on a 2-way and banking on him as our ersatz first rounder next year when the Hawks get our actual pick. Same with Nnaji, but I can't see him slipping to 38.