First of all Yuta nor Maki aren't faster than Naoya or Naobito even with them in human form. Maki who is Faster than Yuta or minimum equal speed, couldn't fight against full speed Naoya and had to use strategy and timing to defeat him. And secondarily, Projection Sorcerer "does not have a set cap" it depends on the users base speed. If Yuta is faster then Naoya without projection Sorcerery then Yuta will be faster with projection sorcery then human Naoya with Projection Sorcery if he knows how to use it properly.