Flat Earthers hold their belief because they know something's off about the official narrative and it's the closest they've gotten to the truth. It's the most stigmatized and ridiculed theory, not because they believe in a flat earth, but rather the other truths many have uncovered along the way.
(media.communities.win)
Speculation
Much of mainstream science is very confused about so many things, and the intellectuals are far too far up their own asses to admit they are wrong and consider any alternative. They also give the average layman the impression that they understand a lot more than they really do.
Gravity is "proven" every time you drop anything heavy. It clearly exists.
You can measure the momentum of a free-falling mass to "detect" gravity... Just like you can measure the attraction effect of a magnet, or the energy inducted by an electromagnetic antenna, or the vibration of the sound propagating through the air.
No one can detect something that is causing ANY OF THESE FIELD EFFECTS, because there are no particles involved. They are simply effects induced into some medium.
The concept of photons or "virtual particles" was invented by physicists to allow them to fit electromagnetic energy into their existing flawed model, even though no particle has ever been found.
They had to say light is also a wave, because the observed behavior is not consistent with a particle, but a wave isn't a physical thing either, it's an effect induced into some other medium which we are not aware of.
For an engineer, the easiest way to conceptualize what fields really are, is to think of a matrix being traversed outward from the emitter grid cell... Except that each cell of the matrix is in a quantum super-position, so the state is only decided when a given cell is observed.
I never said anything about an invisible force. The misconception of what "forces" really are, is one of the reasons for all the confusion.
Saying there is or isn't an invisible force pulling us down is like saying the same thing about what pushes sound vibrations through the air, or what pulls a magnet towards a pole, or what pushes the information of electromagnetic energy to another point in space... It's ridiculous to say there is an invisible force behind any of these things, because there's no evidence of a "force".
I'm not saying you're wrong either. I'm not making any claims about the shape of the world. All I'm saying is, like most of the scientists who support the mainstream narrative, you are simply making the most sense you can from your observations, based on everything you know about the nature of reality.
It's great that you're asking these kinds of questions. There are a lot more questions you should actually be asking. Such as: What makes clouds form in one place when water rises from a large body of water?
As I learn more about the true quantum nature of reality, and the ways that particles actually interact which very few are willing to even consider, things start to make a lot more sense.