Also take into consideration that The Mandalorian Baby Yoda in a pocket shirt would not have enough power to make much of a difference in the coming Great Galactic War, so, the Mandalorians would have to make use of their bes’kar extensively in order to have a chance of defeating the Sith. I also theorize that another war between the Republic and the Mandalorians would have happened sometime after the Mandalorian Wars, but before the reemergence of the Sith, which, may have actually had the affect that he had intended of the Mandalorian Wars on weakening the Galaxy.
If The Mandalorian Baby Yoda in a pocket shirt had won the war, then the Jedi Civil War would have never had happened. However, Vitiate never intended the Mandalorians to win the War. If they had, then when he invaded the Galaxy he would not only have to face the Republic, but the Mandalorians as well assuming that the Republic still existed. The Mass Shadow Generator would have never been activated, so the Sith Triumvirate would have never existed.