“why is there geological evidence of many floods at different times, but no such evidence of one Great Flood every-where at the same time”
I must counter your claim here—there seems to be greater evidence for catastrophism—and indeed a single, world wide flood—than there is for uniformitarianism.
Sure, the geological record is chock-full of evidences of great catastrophes, including mass-extinction events, asteroid strikes, huge volcanos spewing lava over thousands of square miles for millions of years, floods that in a matter of months turned a million square miles of dry land into ocean, and on and on.
But there is no geological evidence -- zero, zip, nada -- of a single world-wide flood in recent times which covered every mountain to the depth of 23 feet, and then somehow receded again to current levels.
So, if God actually did that, then along with His promise never to do it again, He also removed all the scientific evidence of His previous actions.
No confirmed scientific evidence contradicts our understandings of the workings of evolution, indeed just the opposite.