Thunderbolt ports
I have a late 2015 iMac. It has two thunderbolt ports - rectangular 1/2 ports, NOT oval thunderbolt 3. I want to use these because I need to connect some additional devices to my machine. I can't find an any adapters or hubs that would allow me to connect these to anything like modern USB devices. Mini display connectors are available to connect these ports to HDMI, etc. but not USB. Is there any way to use these or are they worthless?
iMac 21.5″, macOS 11.6