Ball earth has the most financial backing and gives many answers to questions, although some are completely misguided. We all owe a ton of gratitude for the scientists who have worked hard to get where we are today, even though there is a ton of bad science out there as well.
Flat earth is a platform of doubt, that is really only right on some points, that disprove ball earth, but has totally failed to prove that flat earth is even possible. Not even a working model of the sun and moon for flat earthers to point to. It's really a place for the uneducated. I already posted a link that supports flat earthers have low knowledge in the science fields.
Concave Hollow Earth is the most ignored, but is the best answer. It has it's own models, proofs, and can withstand tests of stars, ships, planes, seasons, and etc.
I know when this debate ends, but it won't end soon. The mystery will be solved in time.