I have seen multiple mock drafts with Julian Phillips in the first round. I think you have to make the jump if they are predicting you to go in the first round. I totally agree that Phillips is extremely raw on offense, but I think NBA scouts are interested in his athletic abilities, his defense, and his measurables. All of these NBA teams think they can teach the shooting, whereas they can't teach height or speed.
The other thing to keep in mind is that the NBA and NBPA are going to agree to a new contract which will remove the restriction of 18 year olds being drafted. It's possible the 2024 draft is the "double draft" where all the freshman stars as well as the best high school players are eligble to be drafted. He could get pushed to the second round or undrafted status because of the talent in front of him.
For as good as Chandler was for us, he was always facing an uphill battle based on his size. It's just so difficult to be an effective NBA player under 6'2. Selfishly, I wish he would have stayed, but then again, if you're mocked in the first and told by scouts they like you in the first, you have to go. The NBA prioritizes youth and potential over college performance. It's rare for guys choosing to stay another year to improve their stock. Guys like Grant Williams are exceptions, not the standard.