These magical terms are simply definitions for observable phenomena and the calculations, though difficult to some, are no secret. You are free to get an education so that you can enable yourself to understand them. Putting your thoughts together based on unprovable ideas that you admit is impossible to observe first hand is no way to learn anything about the world.
You mean like your gravity?
It is defined as the apparent attraction of bodies toward each other. This is an observation and gravity is the name given to describe that. Science is pursuing more knowledge about it by asking, "How is this happening?" The suggestion about how it works is a theory. However, its a fact that things are attracted to each other, that part is a fact because we can observe it happening. How can you have a problem with that?
The only thing that I observe being attracted to each other are magnets, what do you observe?
For myself it was like this...
Things fall down and as a child not much thought is given to that but nevertheless... They fall.
Then other observations support the observation of things falling down when I notice the behavior of objects rolling down hills as opposed to up hills and so on. Then, I notice that I can give objects inertia by pushing them, throwing them, etc... But no matter what I do they still go down.
These observations about how I can manipulate objects are explained to me by newton. It seems that objects don't do anything unless I (or something else) act upon them, but there seems to be another unaccounted force that makes them do something else (go down).
I hear about gravity and that seems like a good explanation but I wonder why it seems that 2 objects that I can hold are not affected by each other. The explanation in gravity is that the effect is relative to the mass of the objects. Then Einstein proposes that the theory of gravity is equivalent to an acceleration scenario as outlined in the equivalence principle. Those both seem like good explanations. One is dependent on the surface of earth being a sphere and the dependent on it being a plane.
Then I notice simple things like the sinking ship effect and the routes taken by aircraft and ships to their destinations. They all seem to go in a pattern that on the flat maps we are used to, don’t make sense. These routes are explained by using a route appropriate for a sphere. Hmmm.
Then I see satellite dishes and wonder what those are. I notice that they all point up and that the ones that don’t have a different shape that are not actually pointing in a different direction. The reflective signals are still, in effect, pointing upward.
Then I hear about orbits and how in effect satellites and the moon around the Earth and the earth around the sun is actually falling toward the object with the larger mass but never do because of their velocity perpendicular to the surface of the object they are orbiting. Later, I become a meteorologist and actually work with these satellites and the behavior of these are compatible with this orbit idea. I actually verify that the apparent paths of these satellites are correct.
As a meteorologist I learn about the system of the Earth layers of atmosphere. I depend on this mental model to do my job correctly. I also learn about the coriolis and how such an observation is only possible on a sphere. The storms of the world are doing this.
I sail around the world countless times and we again take strange circular routes that contradict that flat maps we use on our maps. To get from Japan to Southern California as quickly as possible we have to arc our way up nearly to Alaska? We took a much straighter route from California to Japan because we stopped in Hawaii but this circular route on the way back was nearly a week and a half less travel time. Hmmm.
Every single day, every observation and everything I do is completely compatible with a round earth. It happens over and over again with a 100% success rate. Nothing is ever contradictory to this. There is no hole to be filled by some missing piece a puzzle when considering the shape of this planet.
The things I have mentioned are only the surface of the observations that can be made and they never fail to be correct.