I would not put anything under a grommet curtain.

I think grommets or rings would result in too much hardware. Consider a sheer roller blind if you want filtered light. For a modern style, here is an Ikea option Skogslover. I have a few, easy installation, work well, inexpensive.

Thanks for the feedback

If you want to control llight and heat use solar shades you get to keep the view and have privacy during the day and just close the drapes for privacy at night

I would not use grommet curtains at all. They remind me of shower curtains.

You could use rods and rings for the outer curtains and some sort of shade on the windows for privacy and light control.