Such a "truest" formula doesn't really exist, or at least what you determine to be the truest is just a matter of definition and taste.
For any equation it's mathematically trivial to come up with a different set of equations that produce the same result, e.g. for example just via approximating the original function with some infinite series that is guaranteed to give back the original result in the limit.
But even beyond such trite examples, it's not unlikely that there will simply be multiple competing ways to model the same data that the equation takes in and spits out that are very different in form and function, and perhaps even in mathematically incompatible ways (this could happen if e.g. the equations model more than what exists in reality but all of reality is described by some subset of the parameters of these equations, like how gravity works for negative masses but such a thing does not exist from what we know).
You could then decide on some reasonable criteria which of all your models is the truest one, but the criteria themselves will be up for subjective debate.
For any equation it's mathematically trivial to come up with a different set of equations that produce the same result, e.g. for example just via approximating the original function with some infinite series that is guaranteed to give back the original result in the limit.
But even beyond such trite examples, it's not unlikely that there will simply be multiple competing ways to model the same data that the equation takes in and spits out that are very different in form and function, and perhaps even in mathematically incompatible ways (this could happen if e.g. the equations model more than what exists in reality but all of reality is described by some subset of the parameters of these equations, like how gravity works for negative masses but such a thing does not exist from what we know).
You could then decide on some reasonable criteria which of all your models is the truest one, but the criteria themselves will be up for subjective debate.