I'm not gonna make a new post for this. The best comparison for Xavier Tillman is Domantas Sabonis. Both crafty finishers. Both great short rollers. Both good passers. Both good rebounders. Both limited but crafty athletes. Both intelligent but limited defenders.
Sabonis is two inches taller, but Tillman has a 4 inch longer wingspan.
Just to be clear, I don't mean comparison as upside. It's unlikely Tillman is ever as effective as Sabonis, but play style they are very similar and I do think Tillman could be effective in that roll.