It is amazing (and a bit insulting) to me how many Catholic paintings and images show Mary as a some sort deity and/or Jesus as an eternal little baby.
Not only is Jesus often a little baby forever, but otherwise he is forever on the cross. It’s as if everything that happened between baby and cross and what happened after the cross is not as important.
It just seems that way a lot of the time.
Your interpretation is based upon a modern understanding, and not the period artistic devices.
The paintings you refer to were intended to demonstrate the majesty and divinity of the child Jesus. An infant conveys the sense of innocence. It also conveys the true, human nature of Jesus. Think Lamb of God, innocent like a lamb, that sort of thing.
As to the crucifixes, there were times when people didn’t believe Jesus actually suffered and died on the cross as a man. The depictions were meant to be graphic, as to also convey the greatness of His sacrifice.