I probably read and studied it more than you have. This is the kind of issue that make Christianity look foolish because a global flood just doesn't make any sense at all.
It does not have to "make sense". (1) Firstly the Bible makes it crystal clear and (2) secondly there is sufficient geological evidence to confirm this. But even if there was no geological evidence the Word of God is sufficient for Christians. How unbelievers look at this is immaterial.
12 And God looked upon the earth, and, behold, it was corrupt; for all flesh had corrupted his way upon the earth.
13And God said unto Noah, The end of all flesh is come before me; for the earth is filled with violence through them; and, behold, I will destroy them with the earth....
17And, behold, I, even I, do bring a flood of waters upon the earth, to destroy all flesh, wherein is the breath of life, from under heaven; and every thing that is in the earth shall die...
19And the waters prevailed exceedingly upon the earth; and all the high hills, that were under the whole heaven, were covered.
20Fifteen cubits upward did the waters prevail; and the mountains were covered.
21And all flesh died that moved upon the earth, both of fowl, and of cattle, and of beast, and of every creeping thing that creepeth upon the earth, and every man:
22All in whose nostrils was the breath of life, of all that was in the dry land, died.
23And every living substance was destroyed which was upon the face of the ground, both man, and cattle, and the creeping things, and the fowl of the heaven; and they were destroyed from the earth: and Noah only remained alive, and they that were with him in the ark. (Genesis 6:12,13,17; 7:19-23).
Kindly invest in
The Genesis Flood by Whitcomb and Morris for a detailed discussion. It is available from Amazon.com.
As to the number of animals, had you read the Bible account, you would have seen that the number was limited to what was necessary to continue reproduction after the flood.