Physics is a model of reality. Reality is objective, but the model we have chosen is very much "subjective" (maybe arbitrary is a better term).

It's easy to imagine that another species might have never conceptualized electrons as little balls orbiting around a nucleus. They are neither balls nor are they flying in circles, those are simply abstractions we like because they appeal to the way we perceive reality. The way we conceptualize electrons leads to issues like the wave-particle duality, so it's likely just a local optimum we got stuck in. Another species might not even think of Electrons as being distinct entities, maybe they think of the electron field as one large ocean with some waves in it, or they subscribe to the single electron theory, or something we have never thought of and might never imagine from our perspective.

"Arbitrary" ("existing or coming about seemingly at random or by chance or as a capricious and unreasonable act of will", "based on or determined by individual preference or convenience rather than by necessity or the intrinsic nature of something" [1]) is a very poor term. Not only is physics highly constrained by what can be observed in the universe, it is also capable of demonstrating (when it is actually the case) equivalences between apparently dissimilar modes of presentation. It is not perfect, but can you present anything that does better?

[1] https://www.merriam-webster.com/dictionary/arbitrary