The "water canopy" theory is a complete failure.I would comment just on this.
Probably 30 years ago there were a lot of creationist videos floating around on the pre flood world and the world after the flood. The major theme was that the pre flood earth was radically different than the post flood earth. Before the flood there was a band of water surrounding the earth. It filtered out the radiation of space and stopped the influx of ultraviolet light. It also gave the earth's atmosphere a higher oxygen content and atmospheric pressure. It was very much like a biometric chamber. This caused plant growth to explode and as dinosaurs were mainly plant eaters their function was to keep the flora eaten back in areas which were not populated. They were the large scale goats of today when it came to eating back the excess foliage as a goat can eat just about any kind of woody foliage.
A reasonable statement.As the post flood earth would have a much thinner atmosphere there would be no need for large animals to eat back flora as there would not be the same growth rates due to a greatly changed atmosphere. And there would be ice and snow during the winters which did not exist before the flood which also negates plant growth like there was before the flood.
You have no way to knowing that "God didn't bring the dinosaurs on the ark". It is true that dinosaurs might have had problems post-flood and died due to the changed environment, like the much lower oxygen content of the atmosphere. But there is no evidence that God excluded them from the ark.So, my point is that God didn't bring the dinosaurs on the ark because they would have simply starved to death in the greatly changed post flood world.
Pre-flood and post-flood conditions were definitely much different. Even the length of a day changed quite a bit.As evidence of this there has been found buried deep underground brass that cannot be duplicated today except in small foundries in which all ultraviolet light has been filtered out.