Gundogan and Dinho play the role differently. Gundogan offers more creativity imo with his chipped passes over and has better passing overall (Dinho still has good passing) and he typically scores or creates more than Dinho. I've seen Gundogan take more shots than expected as a #6 than I thought he would, I think Pep asks him to do this because his shooting is good.
Dinho is better defensively on the counters, I think both are good at interceptions, with gundigan winning by a bit due to his positioning, but Dinho will take more risk in his recovery of tackles and is probably better at it overall, these are the "tactical fouls" other clubs moan to us about, Gundogan doesn't get those as much.
The team adapts around whichever one we use. One isnt better than the other, just different.
End of last season we had an insane like 14 game win streak with Gundogan as DM, that simply doesn't just happen.