There are many brands that still profit off their good name, but by now are just selling generic Chinese designs with fancier enclosures. E.g. my wife bought a Satechi USB-C On-the-Go adapter. One of its stated features is that it supports 4k@60Hz. Except that it didn't work. We tried different 4k screen models from different manufacturers and two different MacBooks and a Windows PC. All of which work fine with a USB-C DP alt-mode cable and a Lenovo USB-C Dock [1]. We contacted their support and they recommend that we do a firmware update. They send you a completely undocumented Realtek firmware updater (Windows-only) that doesn't work.
I was surprised by all of this, because Satechi used to be a reputable brand for Mac adapters. So, I investigated the adapter a bit more and the MAC address stood out. The MAC address was registered to Part II Research, which doesn't really seem to exist anymore. However, looking at their website through archive.org showed that they were a division of the Chinese brand Power 7 Technology. After browsing their website, I found an adapter that was more or less identical to the Satechi USB-C On-the-Go. The same port layout, the same touted features, but with a different enclosure:
https://www.power7tech.com/page/305
Power 7 makes reference designs and sells them to manufactures that rebrand them. This explains why Satechi couldn't provide proper support and couldn't even provide a working firmware updater. They didn't design the device or the firmware. Needless to say, we returned the adapter.
When I was researching this, I found a nice blog post that opens up several adapters from reputed brands (Satechi, Icy Box, Anker) and finds that they are just rebranded generic designs of typically pretty miserable quality:
https://overengineer.dev/blog/2021/04/25/usb-c-hub-madness.h...
After several bad experiences with adapters and docks that do USB over USB-C, I try to buy Thunderbolt accessories when possible. You see some of the same crap (Realtek RTL8153), but on average the quality seems to be better.
[1] The 4k@60Hz support, the Lenovo Dock has other issues.