Look at Houzz photos "roman shades on bay windows" and you will see a bounty of delightful window treatments for bay windows. It is assumed the space is a main living area, so the formality or casualness of fabric for romans would depend on the planned furnishings and décor for the room. Is this helpful?

I recently bought a product called Veilish. It’s a window film made with fabric material. It’s semi-transparent, so it can provide indoor privacy without blocking the view outdoors. The best thing is that it is self-adhesive, and it can be installed and removed easily, so you don’t need an installation expert. I think you will definitely be satisfied with this product.

Have you thought about bottom up top down pleated blinds or honeycomb shades? Minimal in design and able to install as inside mount to a shallow depth of only 1/2 inch. Here are some client pictures and how they solved their bay window challenge.

Master bedroom with a total of 7 windows, including a bay window area, which makes it a bit tricky. We live in Seattle where sun rises at 5am in the summer, so blackout is a must. In previous house, we had automated cellular motorized blackout shades which worked well. We valued the automatic nature, because otherwise we probably would have lived with blinds permanently down because we don't take the time to open them every morning. but automated shades for each window feels too expensive and not very practical with 7 windows. I am wondering if floor to ceiling blackout curtains on a ceiling track (ideally motorized and automated) would work well for the long wall. This would mean cutting out the bay window area w the curtains. 1 downside is it would be inconvenient because we will eventually put a loveseat there to watch TV sometimes. How would you do window treatments in this room to achieve automated blackout light control? Cellular shades vs curtains? Any other option we should consider?