Can you post a picture of the area you are trying to cover?

you can use the brackets provided, and get a steel pipe to cover the space with a support in the center (or whereever you can accomodate a break. ... I have also used a dowel to extend and existing rod, and have used a pvc water line (painted to work with existing brackets)

Necessity is the Mother of invention.

Here are some examples of long rods that are pieced together to create the long expanse & links to those rods.

https://www.draperyrodsdirect.com/decorative-drapery-hardware/metal/wrought-iron-collection

https://www.draperyrodsdirect.com/decorative-drapery-hardware/metal/designer-metals-collection

https://www.draperyrodsdirect.com/kirsch-k-rail-9437k-baton-draw-rod?gclid=Cj0KCQjw37iTBhCWARIsACBt1IzE9B5JfI6VBVg4wZ-eYAz-Qx8jvfInTo_UpcuJvPU4Sub10vU30-IaAplvEALw_wcB

I have a bank of windows that is 38' feet long. We used conduit pipe and conduit connectors to span the distance. Ours is 1/2" diameter. (Don't remember if that's inside or outside diameter.)

Also used curtain rod brackets at each connection joint, plus more, spaced as needed. Combined with "C" rings, so the drapes can clear the brackets.

Electrical conduit is available in several sizes in 10' and 20' lengths

Clean thoroughly, spray with a bonding primer, and then with Rustoleum in your preferred finish.

Most people don't have trucks to haul pipe in so having drapery rods not longer than 8ft that get pieced together works for most people. There is no escaping intermediate supports unless you decide to use a ceiling mounted track.