To start, I am in fact a Round Earther.
Bickering isn't going to resolve these issues.
I
am referring to both sides of this argument.
Anyways, the burden of proof is in fact placed on the Flat Earthers due to their claims. It is a widely accepted "fact" that the Earth is round and thus, any claims otherwise such as FE theory, need to be approached with scientific evidence. A wide variety of evidence has in fact already been presented on these forums for RE. Attempts to counter them have been made, but the explanations for why this evidence is flawed or discredited themselves cannot be proven.
Gravity, the sun, weather patterns, NASA, satellites, horizon lines, magnetic poles, physics in the creation of the Earth, the moon, seasons, pendulums, celestial bodies (including other planets), the Coriolis effect, etc. were all presented by Round Earthers as existing evidence for an RE model.
To my knowledge, every case was either adapted to fit FE or discredited by being considered part of a massive pointless worldwide conspiracy.
These are simple and ideal forms of evidence. It is simply time for Flat Earthers to step up to the plate. Should there be no substantial evidence, no reason to believe in a FE would arise. This is only proof that the FE theory was invented by someone with a creative imagination which would make RE infinitely more likely.