There are many logical failures in this argument.
1. You are only focusing on the changes that would lead to a specific amphibious creature. What you don't factor in is all of the viable evolutionary pathways that do not lead to your specific result. This is known as the Texas Sharpshooter fallacy.
Texas sharpshooter fallacy - Wikipedia, the free encyclopedia
2. You act as if the fossil record does not have many transitions for extinct lineages. This would require you to search the entire fossil record to make such a statement, which obviously no one has done. In fact, I doubt we have searched even 0.00001% of the fossil record. On top of that, you also make the assumption that every single transition produced a fossil, and that this fossil survived to the modern day. I don't see why these assumptions should be true.
I guess that you are unaware that people win the lottery all of the time?
We call this an argument from incredulity, which is a logical fallacy.
Argument from incredulity - RationalWiki
Reality has this strange property of not caring what we humans find believable. If we find it hard to believe that it is the Earth that is moving, and not the Sun, reality doesn't care one wit. The Earth is still the one that is moving, in reality.
We have many exmaples of transitional fossils.
List of transitional fossils - Wikipedia, the free encyclopedia
More importantly, all of the transitional fossils, and fossils in general, fall into the predicted nested hierarchy. All of the fossil evidence supports the theory of evolution.