Please help me trim out openings

I think before you do any changes structurally, I'd check to make sure that any remodels that have been done on the house previously work ok in terms of load bearing, etc. The wall to either side of the fireplace look unusual to me and low. Would want to make sure that structurally there isn't a problem with any work that was done before. There's lots to think about In trimming out the openings, for instance, with those walls to either side of the fireplace, given that you have so many other doorways in close proximity, One option would be to match doorways to either side of the fireplace in height and trim to the other doorways which may have been what they already had. You can make it rounded but it is more work and expense. It may be with the last remodel that whoever did it was trying to get away from the "all the same square look" of all these doorways so close together with a difference in height and finish without trim and this might even be a better look for these rooms, given that. All things to consider. I would visually try to mock up any changes first to see what you'd like best. Another option would be just to frame out the top of the doorways lower on either side of the fireplace without the trim or round it without the trim as well. As for the other doorway, I think it would look better with either the original french doors up or possibly some replacement doors that match the space if don't want them up now. Good luck!

Would replace the doors with new French ones, but try not to mess up the way the original ones install, so you can put them up later when you want. Temporary option to soften the room would be to hang drapery at those openings, with or without the doors.

I would add trim and mouldings on those larger openings like you have on the other openings into the room. Perhaps lower the entrances with a header, so they're all consistent. Don't put arches...it'll look out of place with all the straight line openings. I like your ideas of trimming out the fireplace wall. Make it look as thick and rich as your other entrances. It's a beautiful room.

Thank you for the suggestions!