here is an idea for you

guess the picture didn't attach, I saw it here then poof it's gone, it was a staircase with part wood part white paint. Houzz picture file is full of them, check them out, since it didn't work for me to post one

Your furniture and furnishings are in traditional and antique mode. I realize to you the trim is popping out at you because the window change is recent, and unlike what you are used to. However, I'd live with it a while before painting. I honestly don't think it's bad at all. I think the wood trim goes with your rooms better than if you painted it white, but that's my opinion.

I always recommend that my clients paint over dark woodwork regardless of their style, as it really brightens up and updates the space. I would paint the trim a true white. Try S-W's 7006 Extra White or 7005 Pure White. For a cooler white, try their 7004 Snowbound.

Try to match the white to the SW colors of white. Get samples if necessary, at the least take home color strips of their whites. I think it would really update the house and will look great with your furnishings. But you must paint ALL of the trim.

We had a similar dilemma. Our staircase is almost identical. Some of our rooms already had been changed to white by previous owners. A majority still have wood twin. When we redid our kitchen we decided to change all of that trim white. We changed all baseboards white and also any door trim that touched the baseboards. We left the window trim brown. I really like how it turned out. Could you maybe just paint the trim around the white windows and see how that looks. If it looks really off with the baseboards, could paint the rest later. Is it in your budget to replace your baseboards as they are labor intensive to paint over without getting paint on floors/walls? I have to say I love the white trim more than the wood in our house but there is so much wood so we have found a way to make it work. In my rooms with white trim I try to incorporate some of the wood tone through furniture, picture frames, etc. where stained twin remains, I make sure I have white in my decor. Not sure if that makes sense? We have yet to change our staircase. It is all stained wood and I will likely paint the spindles white at some point. Our white is Valspar ultra white semi gloss. It is a brighter white. Not off white. Changing our baseboards to a larger profile made the house look much more updated