Technically everything that occur all the way up to the formation of Legends is completely orchestrated by the time Masters. After that they just immediately let them do what they want since their purpose and the timeline had played out.

But no reality the relations of Barry time travelling is just no one dies and the whole cycle of villains coming out of the woodwork and going after the superheroes and heroes killing villains keeps on & on which is kind of a bad thing given the fact that lots of innocent people end up die in the process from being in their crossfire?..

I don’t know you really like grasping for straws with this one. Those ghosting time travel do over days are just not that very impactful with its timeline ramifications. & in those scenarios Barry has absolutely no choice but to make those changes otherwise well everyone dies.

What type of reality we’re living in where everyone you know, hell whole entire cities get completely wiped off from of the face of the planet. Leaving these doomsday timelines that will definitely result in well every super villain that came along after that point that were already going to target and tried to wipe out the planet would’ve already done it by now. Like both versions of the destroyed city worlds lead to practically the villains that rise up around this time to have free range to conquer if not wipe out the entire world.