But gravity isn't really a force. In the same way that inertia is not really a force. It's just an artifact of the coordinate system being curved.
But I'd say that the force that eventually moves the needle is not gravity, but the one that the table applies to the scale to prevent it from going down.
The contact camp agrees with you.
I'm in the contact camp: a scale or balance blocks the freely falling motion of the weighed item. Or, by equivalence, the weighing apparatus (and anything supporting it, be it the whole planet Earth or a rocket engine) imparts an acceleration (i.e., applies a force) on the weighed item, so the latter cannot be in geodesic motion.
The net force is zero.
When forces balance, they may balance to zero so the object in question doesn't move; but there is compression or tension in it. The scale measures that stress. If you remove either gravity or the restraining support (floor, table, ...) the stress goes away.
Force is defined as mass times acceleration: F = ma.
A body falling due to gravity experiences a force because it has mass and is accelerating. That's how force is defined.
Gravity is a pseudo force.
Centrifugal force is pseudo, but centripetal acceleration isn't.
In what reference frame can we properly understand gravitational attraction, if the obvious one is fictional?
The frame of reference is the curved 4 dimensions space-time
But you can create a black hole by putting enough photons in one place.
F = ma
According to general relativity, in absence of forces, an object follow a geodesic in space-time. Which we approximate to an uniform motion in straight line for high school physics. But masses "curve" the space time, so there are no straight line.
If there was no intramolecular forces to keep the apple on the tree, it would follow a geodesic that would make it fall towards earth. The same way that if the seat was not applying a force to my back, I would be pushed backwards in an accelerating car.
https://en.m.wikipedia.org /wiki/Kaluza%E2%80%93Klein_theory
If I recall correctly, the description of charged matter is somewhat problematic.
There is https://en.wikipedia.org/wiki/Kaluza%E2%80%93Klein_theory
That's not true. The "all masses fall at the same speed" thing is only true when one mass is much larger than the other. (Well, it's never actually true, it's more "is only a useful approximation".)
So heavier masses follow different trajectories in a gravitational field, just like more charged particles do.
A heavier particle falling toward the sun will cause the sun to move which will in turn influence the path of the particle.
We were comparing the motion of a charged particle and a mass particle.
The equivalence principal was never mentioned.
"Even Phenomenally Dense Neutron Stars Fall like a Feather -- Einstein Gets It Right Again"
https://public.nrao.edu/news/neutron-stars-fall/
More detail, Archibald et al. 2018, "Testing the universality of free fall by tracking a pulsar in a stellar triple system" (Nature volume 559, pages 73--76 (2018)) preprint: <https://arxiv.org/abs/1807.02059>.
If universality of free fall fails, so does the single metric / purely geometrical theory of General Relativity. That would be very exciting, so it has been looked for a lot.
https://duckduckgo.com/?q=tests+of+universality+of+free+fall...
You can recover a bit from your statement by considering that solutions of the geodesic equations can be a bit messy in manifestly relativistic or multi-body systems, and the equations of motion of components can be even messier. Nobody would disagree with that (it's why there's e.g. the (gravitational) Self-Force methods and the like; see e.g. <https://arxiv.org/abs/1501.07322v3>, which (cf. your second sentence) is useful when a compact mass (e.g. a neutron star) is in a close orbit around a 50x+ more massive black hole, bottom right corner of <https://en.wikipedia.org/wiki/Post-Newtonian_expansion#/medi...>).
Even velocity and potential energy.
Mass is just one kind of energy.