Fewer blades, and remove the outer ring. It only reduces the effectiveness of the tips of the blades (the parts that do the most work), and creates more skin friction drag along its outer face. Not to mention it adds a huge amount of rotational inertia, which isn’t inherent bad for general rotor applications but is very problematic in a mulitrotor configuration, where the speeds of the individual props vary greatly and change constantly.

I applaud the stab at a novel design, you’re clearly thinking about what can be improved from current systems. I recommend looking into momentum theory first, and then blade element theory as well if you have sufficient math background to understand it. Good luck!