This is just my opinion and not standard catholic teaching:
I think the physical evidence is overwhelmingly against a global flood. Most people using a 6,000 year timeline place the flood around 2,000 BC which is pretty close to the time the great pyramids in Egypt were built, which would mean either the pyramids survived the flood unscathed or they were built within a few generations by Noah’s grandkids. It also really contradicts everything in geology and biology.
A local flood doesnt make a whole lot of sense either, since why would you build a boat instead of just leaving the flood zone?
Ultimately I think you need to go for some sort of metaphorical or mythical interpretation, or live your life denying evidence. I dont think God would require us to ignore evidence, so I dont think belief in a literal worldwide flood is necessary, and in fact I think that teaching turns a lot of people off of the gospel.