I would keep using your supplier. Using China and Indian suppliers is probably OK, however as we know from other Chinese products i.e. toys bought through temu platform, they do not follow the quality requirements ans authorities check as our national suppliers has to do. This is down to the local supplier and how much you trust him. If you’re changing supplier, you open yourself to risk in terms poorer quality product. This is stuff you’re eating - keep the supplier you are happy with.
Lots of variability in this. I have bern compounding Chinese powder since I flagged a massively poor product that many here had been taking. At the time, just powder compounded with lactose. 1 mg per day back then. My trough levels were identical to Rapamune. Mass spectrometry was the essentially same as reference (done by a friend).
The only change I have made is to put it in enteric stable capsules and gone with intermittent doses.
My pal buys multiple medications from the same supplier, with the same results.
I am now going to compound pioglitazone (steroid induced Diabetes) and bempedoic acid. Both insanely expensive in Canada.
I see no reason to change.