Curtains For Arched Windows Can You Drll Into A Metal Window Frame To Mount A Curtain Rod Bracket?

Can you drll into a metal window frame to mount a curtain rod bracket? - curtains for arched windows

I have a large window (about 92 inches wide) with an arched window directly above. I am willing to put up curtains in the arc of light through the window, but as the arch above the window to install drywall there for me supporting the curtain rod in the holder. I must have a support center, because the window is so far and I have to curtains. Is there anyway, apart from mounting holes in the window frame to the supporting structure made of metal? and if I stick to the metal frame, it is safe?

Thank you in advance for your advice and your help.