It's not that hard to invent powers for villains that still make them challenging with a speed disadvantage.Kubo wrote himself into a corner giving Ichigo super speed as a bankai, speed is too broken of a power when fights are fought/settled mostly via melee. Either you give all your villains unique powers that can negate or handle a speed disadvantage or you say fuck it and just forget about that super speed power.
Like give a villain super tough skin or regeneration, so it doesn't matter how many times the hero hits them. Then the hero has to think of other ways to use their speed to win.
Or hell, just come up with something broken. Bleach already has tons of abilities that would be hard for a speedster to deal with, like the 2nd Arrancar's aging field or Shinji's reversed perspective.
Or even make a villain whose gimmick is super speed, and then have that villain be the hero's rival/nemesis. Then write some fights about them being crazy fast.
Super speed really isn't that hard to write around, provided it's not completely broken super speed like the Flash's. Kubo just sucks.