Is potential energy necessary? After doing so much research on the concepts of work and energy, I feel like Potential energy is more like a 'dummy' (I don't really know what word to use to describe it) energy concept defined so that we can say that isolated systems have constant energy, like I feel that we could interpret/treat all forces (conservative or non conservative) as the same (like how we normally treat non-conservative forces (we treat only them as '
"external forces" when we say "doing work adds energy to a system")), and this would not lead to any contradiction/fallacy (of work energy theorem, etc) and science would progress as usual, but the only frustrating/unsatisfying part would be that conservative forces would prevent the existence of 'truly isolated systems' as gravity would always a exert an 'external force" and is something that inherently exists because of mass.
Am I right in thinking like this? Like my question suggests that what all we consider as "energy" could depend on how we choose to define it. Is this a debate that actually happened historically between scientists on what to 'interpret'/'not interpret' as energy?
 A: Yes, you are right. In fact, we technically don't need the concept of energy at all. We could do classical mechanics with Newton's laws, and be done with it.
However, keep in mind that concepts in physics are defined precisely because of how useful they are in describing the world around us. There would be more frustration than just "that conservative forces would prevent the existence of 'truly isolated systems' as gravity would always a exert an 'external force" and is something that inherently exists because of mass." Potential energy has much more importance beyond introductory Newtonian mechanics. It is essential in Lagrangian and Hamiltonian mechanics which can handle mechanics ideas way better and more eloquently than Newtonian mechanics can. It pops up in electrodynamics in terms of potentials that greatly simplify work. And then in QM, the Schrödinger Equation relies on the concept of potential energy (relating back to Hamiltonian mechanics). Past that point, you essentially don't even think in terms of forces at all; you are mainly thinking about the energies of the system.

Like my question suggests that what all we consider as "energy" could depend on how we choose to define it.

This is true of literally all definitions in physics. We choose to define things in such a way that they usefully describe how some physical process works. In the case of potential energy, from a Newtonian perspective, it is really just a mathematical trick and a simplification to help explain things more eloquently (conserved quantities always make things easier). However, once you move beyond Newtonian mechanics, you will find that potential energy is a more fundamental idea than what it originally seems to be. Instead of forces determining the potential energy, it looks like it is the other way around: forces (how the motions of particles are determined) arise from potential energy.
