I realize your question refers to a USB Type-A hub, where as below I refer to cables and adaptors. However, the same issues, with respect to the cables and adaptors, would also occur with hubs.
Actually, cables and adaptors with a USB Type-A plug and USB Type-C receptacle are not defined or allowed by the USB Type-C® Cable and Connector Specification Revision 2.1. This is stated in the last paragraph of Section 2.2, which is repeated below.
USB Type-C receptacle to USB legacy adapters are explicitly not defined or allowed. Such adapters would allow many invalid and potentially unsafe cable connections to be constructed by users.
However despite this fact, there of plenty of such cables and adaptors which can be inexpensively purchased. For example, see this the question Add USB-C ports to an old 2014 iMac. I should point out that this type of solution would limit the maximum data transfer rate to 5 Gb/s.
The safer route would be get a Thunderbolt 3 dock and connect to the Mac through the Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter. For example OWC offers this Thunderbolt 3 Dock. I should point out that this type of solution is significantly more expensive.