Don't agree fully here a good nutrition program can help even when you crash in my opinion
Do agree energy management is necessary
Nutritional supplements and diet can help you when you have clear deficiencies (e.g. B12 folate etc), however if you routinely use more energy than you have they won't make a noticeable difference. The point is, pacing will give you far much more useful energy in terms of scale of improvement by breaking the boom and bust cycle. Supplements will top that up somewhat but you can't expect the supplements to allow you to carry on exercising beyond your limits. It's more about symptom relief and management than cure.
You are unlikely to find a self hacked cure using alternative therapies but you may be able to improve your quality of life ( by reducing the impact of crashes, improving cognitive stamina, gut problems etc) and perhaps slow the decline.
Regarding heart rate monitors, I use a Fitbit blaze (there are loads of others...I recommend searching threads on PR) I keep my heart rate below cardio and in the lightest zone (Fitbit call in the fat burn zone) if my heart rate goes above 100 I slow down, if it goes above 120 I stop and rest.
Symptom trackers are useful also. I use moodtrackerT2 but others are available. You can program scales to whatever you want ( histamine skin rash, joint pain, headache severity, heavy legs etc etc) and group symptoms (up to 10). This is quite good to identify symptoms as warning signs for impending doom. As soon as my IBS flares up and my headache and joint pain increases, I know that I need to reduce my expectations as to what I can do since a crash will result if I don't slow down. Sometimes the crash will happen regardless, but it's good to have a bit of prior warning.
When you pace properly you still get things outside your control affecting you such as pollen count, temperature, unforeseen drains on your physical and cognitive energy, but it's miles better than the boom or bust.
Everyone goes through the stage of thinking they can beat this by intervention. There is no cure at the moment. The best strategy is to maintain what you have.
Of the cases that spontaneously remit there is no understanding as to why some do and others do not. I think I saw that remission is more likely if you are younger and have had an infection type onset but I can't recall exactly.
Remission may just happen regardless of any management technique or treatment.