There is one American company making comparable products, https://www.anzurobotics.com/. If I understand correctly, these are basically DJI hardware with American software. I don't know if they use DJI control boards or manufacturer their own but their FAQ does mention they license tech from DJI.
As for the quality, I’ve ordered a few products under some pretty outlandish names and I can’t say that quality was any worse than that of most other no-(real)-name things sold on Amazon.
https://overengineer.dev/blog/2021/04/25/usb-c-hub-madness/
Now, for hubs, I didn't need a full blown thunderbolt one, but my current hub this:
https://www.amazon.com/dp/B0F5PY4F2N?ref=ppx_yo2ov_dt_b_fed_...
which works fine - I looked at some competitors with 2x and 3x the money for the same and sometimes lesser specs.