Usb 3 hubs with a USB-C upstream certainly exist, all the docks out there are functionally that, and there are also dedicated hubs as well.
Here’s the one i use:
Anker USB C Hub, Aluminum USB C Adapter with 4 USB 3.0 Ports, for MacBook Pro 2018/2017, ChromeBook, XPS, Galaxy S9/S8, and More https://www.amazon.com/dp/B07DFYQXY7
Here’s the one i use:
Anker USB C Hub, Aluminum USB C Adapter with 4 USB 3.0 Ports, for MacBook Pro 2018/2017, ChromeBook, XPS, Galaxy S9/S8, and More https://www.amazon.com/dp/B07DFYQXY7