i am also very limited in how much exercise i can do due to low ATP
That comment keeps popping up in my thoughts, because I think it might not necessarily be true. Not that it can't be true, but without an actual blood/muscle test under load, it's not the only explanation for what we feel as physical limits. There could be a problem with the signals sent from the brain, or with signals received in the brain, or some other physical or chemical problem not related to ATP levels. Our brains do get signals from the muscles that we interpret as fatigue levels. What if the interpretation part became overly sensitive, so that even the slightest signal of fatigue became interpreted as "100% fatigue, can't possibly do any more"?
An EMS unit would be a good test of that, since it would bypass the brain's involvement. If your muscles really are limited by ATP production, your muscles should quickly and gradually stop contracting from the EMS pulses. If your muscles continue to contract the same amount, then it's not ATP limitations. If your muscles continue to twitch fully, but trying to move the muscles intentionally gives you the "there's no energy left in the muscle" feeling, then it would more likely be a brain function problem. Not psychological, but a problem with nerve signals.
If EMS triggers PEM, it's possible that starting with low level sessions (intensity and/or duration) could gradually rebuild your tolerance for muscle exertion without triggering PEM. EMS might not prove effective for you, for one reason or another, but wouldn't it be nice if it did work?
PWME have a vast number of potential treatments that we could try. Many of them are expensive or difficult, and very many of them have very low probabilities of working, and many have significant probabilities of negative effects. Some however, are fairly cheap and easy to try. Some can also be beneficial in terms of discovering something that you should avoid. For example, if EMS showed that even slight exertion caused significant problems, you might want to figure out ways to avoid the exertion of bathroom visits or washing.
I'm not a proponent of EMS (I don't have one). However, since you asked for suggestions, EMS seems like something worth trying. If you do try it, please post the results so that others in a similar situation can decide whether it's worth trying too.