I fully believe Venat/Hydaelyn is a good person. Just not sure she is a smart person with the decisions she has made.

Minfilia's first death being a good example as stated above.

Also there is no way she could have known the Sharlayans would build a ship that could go and face Meteion. Her giant aerther battery could have been used for the Moon, but Endwalker made it seem like using the moon to get to the edge of the univers was not a real option. At the point we went back in time, I don't think we knew about the Sharlayan ship to even give her future knowledge about it. Hydaelyn never made a plan to get us to Meteion to fight her.