Yeah, that sort of depends on the level of physics you’re talking about. regardless, it’s still a property of stuff even if that stuff is not always matter. if you want to go off on the weeds on that, go for it.
even so, energy is not something that exists, but a quantified attribute of things that do exist.
Energy is not only a property of matter. Photons have energy, no mass, and are not matter but in fact force carrier particles.
Yeah, that sort of depends on the level of physics you’re talking about. regardless, it’s still a property of stuff even if that stuff is not always matter. if you want to go off on the weeds on that, go for it.
even so, energy is not something that exists, but a quantified attribute of things that do exist.