In the titration of sulfuric acid with potassium hydroxide, how the potassium and sulfate ions affect the pH of the solution?

Neither potassium ion nor sulfate ion affect acid base equilibrium. The $p H$ will remain constant.
Well, $p H$ remains the same. What about concentration? What are $\left[{K}^{+} \left(a q\right)\right]$ and $\left[S {O}_{4}^{2 -} \left(a q\right)\right]$ after dilution?