Question about flat earth to flat earthers or rocket scientists

I saw somewhere in a video that the thrust / velocity / math in regards to getting a rocket off the ground had to do with the earth being flat and not having to taken into account gravity, or something of that sort.

Im wondering if anyone had any specific information to share in regard to this since im having a hard time believing a. the earth is round and b. the earth is flat.

its weird that you have so much hate and negativity towards people who have a certain belief, but personally i saw some evidence that made me scratch my head and go against the grain, and id like to kind of verify that evidence before i decide anything.

so yea if anyone has any information about the rockets and howw they need to be built based around certain atmospheric anomalies or not, please post here or point me in the direction