Not sure this will answer AATW's original thoughts discussed in the first 4 posts of this thread, but I did think about an interesting experiment that could be tried.
To date, I'm unfamiliar with any FE arguments against the generally accepted physics of how waves travel. Specifically, I'm thinking about how sound and pressure waves travel radially outward from a fixed source at equal speed unless an external force acts to change their path. I'm unaware of any proposed FE theory, such as EA, that refutes this.
So, the experiment would be to initiate a sound or pressure wave at a given location, and then use the various measuring sites across the earth to time when that wave reaches them. Knowing the speed of the wave, the distance from the source could then be calculated and various models could be compared to how that data aligns with the model.
The only issue with this experiment, is that the energy required to perform the experiment is quite large and the expense and logistics of performing the experiment basically make it impossible to perform.
Fortunately for all of us, Mother Nature cares nothing about expense and logistics and decided to perform the experiment January 15, 2022 at Tonga.
This would leave FEers to explain how the data from this natural experiment aligns with the RE model but not any of the FE models.