Sometimes I get PEM (or what I believe to also be PEM) where I am more tired/fatigued/weak than normally, have some muscle/bone/joint aches and a super sore throat. I don't feel horrible though
I'd call that moderate PEM.
For me, a certain level of PEM falls into the category of acceptable consequences of doing things I enjoy. These have been calibrated by trial and error so they don't usually trigger severe PEM.
I have mild PEM (symptoms at a rather lower level than you're describing) quite a lot, and I
always rest through it. Once it's fully passed I can choose something else from my list of enjoyable-but-restrained activities without risking an accumulation of PEM.
It doesn't always work, of course. I can feel as if I have the capacity to do something and be confident I'm rested enough, yet I get worse PEM than usual.
For me, pacing means avoiding PEM accumulation whenever possible. I'm moderately ill, though, not severe, and I also use a powerchair. Walking even short distances burns through my capacity incredibly quickly, so limiting how much of it I do frees up capacity that I can use for other things.