Thanks! , I actually used a simple method to design bosses, first i design it on paper (with phases, what type of attack is it), then i animate them with the animator in unity, and lastly i just use 1 method for each attack to add effects, velocity, color change, etc... and then control the attacks from the animator (bcz it's designed like a State-Machine).
although it still takes some time bcz each attack needs it's own system, meaning you are designing each move by itself.