Is it possible the stain class is causing a cast? If so, it might be ideal to get several samples and test them on the wall and look/take pictures at different times of day/light and pick which you like best. You might like Eggshell Yarn by Magnolia Homes. I believe they have it at Ace Hardware Stores.

Hi! Thanks so much for your advice, I do really like the Magnolia color you suggested and I think I will try a sample on the wall. I'm including more images to better show the stained glass and other possible factors contributing to the issue. It really surprised me, because Agreeable Gray looks like a very neutral (if not warm) gray but in my room it really does look like a baby blue...which is very disappointing!!

This looks like it would complement your flooring & fireplace

I think you need a warmer white, not a gray, which can still be neutral. Your tan tiles will look better with a warmer color also.