On a serious note - they have fed us earthlings a LOT of fakes so there is def something going on that they don't want us to see. Is it flat earth in a semi-dome with waters above? I don't know.
I believe space probably exists. I believe the earth is round. I believe it moves through space. I believe we may have gone to the moon, etc..
But I have no direct experience of any of that. Or of much. I can watch an Obama speech today that isn't Obama speaking. There is very little about the outside world I can claim to KNOW. I have LOTS of direct experience of propaganda and lies being taken as fact because it's repeated often enough.
That said, I'm not going as far as the earth is a frisbee under the semi-domed firmament made of waters.
That said, IF THAT TURNED OUT TO BE TRUE, I would be surprised in a "well I'll be a monkey's uncle" kind of way, but nothing would be out of keeping with my world view which is, essentially, "I believe what I've been taught to believe largely, and I hope a lot of it is true BUT I'm also keenly aware of how easy it is to fool ppl - you need only repeat things from seemingly different sources (which are often from the same source) and we will believe ANYTHING at all."