One big issue, is that energy is an abstraction

It tells you a lot of useful things, with very simple math, but you can't ever measure energy directly. So you should give up the idea the energy is a actual "thing" but more of a "label".

So heat, is just the label that we give to a body whose particles move in a disorderly fashion. The more they move the more heat they have. (Actually to be precise heat is how much of the movement of the particles is/can be transferred to another body, but the point stands)

If you consider one single particle, it can't move disorderly, because relative to itself it always moves straight, so for a single particle we prefer to use the label kinetic energy, because a body whose particles move in an orderly fashion is simply a moving body and not an hot one.

Once again, heat and kinetic energy, are functionally the same thing, just two different names for two facets of the same phenomenon.