very interesting! phenylbutyrate is worth a try, it is also a treatment for ammonia detox.
The first treatment to try for PDH impairment is Thiamine, co-factor of PDH:
this study is about babies under 2 years diagnosed with PDH deficiency:
[Thiamine-Responsive and Non-responsive Patients with PDHC-E1 Deficiency: A Retrospective Assessment
Seventeen patients received thiamine treatment: eight did not respond, four showed sustained response and the others responded temporarily/questionably. Sustained response was noted at thiamine doses >400 mg/day. ........ However, this distinction is equivocal and treatment with thiamine (>400 mg/day) should be commenced on all patients suspected of having PDHC deficiency.]
As you notice, the dose of thiamine is very high,if you compare it to the small weight of a baby.
Some ME patients here seems to respond well to high Thiamine dose.
I do myself benefit from high Benfothiamine doses, but sometimes have thiamine injections when it is not enought, and also supplement with B12 injections (hydroxo B12).
Keto diet has been tryed for PDH deficiency with some successes and some ME patients are doing well on it, (although pancreatitis can be a side effect in some cases)
If you have poor enzymes, maybe a enzyme supplementation could help?