Hello, I am planning to add a wireless link for redundancy. I would like to know if, by adding the second link, I need to have a MikroTik router on both sides to configure OSPF, or if I can create OSPF with just one router and an unmanaged switch on the other side.

here you can find a image for better explain
https://ibb.co/VpFLDMq

Ospf needs a device that can run an ospf daemon on both sides. Sessions are established between each participating peer