He is not a "smart" defender yet, clearly better than he was in CLE though. But he has the advantage of physical tools for his size ,if he is healthy, to at least slow down and disrupt the flow of the offense. Few occasions has forces scv's though that I can remember. He is not going to stop anyone with elite handles, or that has a lot of size on him. But so what? He won't be better than most players his stature except he is still getting stronger and not maxed up yet imo.
His game is all offense in the pro vs con chart, compared to his peers right now at the same positions, and the defense will probably always be somewhat of a liability- even as he gets smarter.
I don't think it will matter though, if the roster is constructed well. I mean unless this team when the rebuild is over, has the same type of guard playing with him all the time. I think this was why CLE did not want to pay him, or retain him, because Garland was the same type of defensive liability or worse.