I have no idea how many animal species existed when the Global Flood destroyed the pre flood world and reshaped the single land mass to what we see today, but I accept the Bible in faith as written; the Bible tells us that God brought all the land animals in whose nostrils was the breath of life, and that is good enough for me.
Ultimately it greatly depends upon what God classified as different animals.
It seems reasonable to me that what God classifies as a kind is broader than what we classify as a species today, thus the number of animals that God brought to Noah would have been less than the number of the man-made classification ‘species’ that we use today.
Again, the disparate worldviews that we each hold to, influence how we interpret this.
There have been countless floods that have killed millions of people over the past four thousand years, since the Flood of Noah, therefore, if the Flood of Noah’s day was merely a local flood,
1.) then why did God say the purpose of the Flood was to destroy all flesh, if there were people alive elsewhere that weren’t affected by the Flood?
2.) then why did He say He would never again send a Flood to destroy all flesh?
Surely you can see that 1 & 2 above make it clear the Flood was universal over the whole earth (Earth) and destroyed all life as the Holy Bible plainly tells us.