TBH, 'Custom aluminum extrusion' - this is not a big deal at all. In China, the tool for this is < $1k and for what appears to be about 6 inches, perhaps its a dollar's worth a material if it was WAY overpriced, most likely less than 50 cents. And the tool will last for a long time...
As far as the chips go... I've had much better luck with Asian chip manufacturers -- generally about 1/3 the cost for similar parts. Most have a decent english datasheet. LCSC is a good place to find them.
That said, the advice we got from most of the people we were quoting with was to get the tools made in China, import them to the US and produce the parts locally. We didn't end up doing that but I remember being amazed at the crazy tool quote arbitrage...
Actual processing is much less of a difference, especially at volume. So it makes sense to do tooling in China, production in the US.