Can you post more photos of the entire space? Whatever you decide to do with the large wall has to play nice with all of the surrounding decor.

A nice large, ornate mirror would look beautiful at the end of the dining hall! And this one is on sale at the moment too: Click here for the link on Amazon.

And on the longer wall, if you took these gorgeous gold sculptural plates (they come in packs of three) maybe two packs, and organized them in a way you like it would look amazing! The gold in both pieces helps bring some more color and interest into your space without disturbing the neutral tones you have going on already.

Click here for the link to these!

#amazonaffiliate

You may like large, colorful artwork inspired by the colorful calendar you already have. This is from Etsy.

Indigo Blue and White?

You need to replace the Venetian blinds with lightweight Roman Shades inset in the window. And new chair pads that coordinate and artwork. Get frosted bulbs to eliminate the shadows...and dimmable.

https://www.selectblinds.com/roman-shades.html?productId=1697&width=36&height=60&colorId=11130&K=Color%7C2&utm_source=bing&utm_medium=cpc&msclkid=37b4e1684f2a1d3d987b85cf20096ea8&utm_campaign=BING_SmartShopping_Romans%26Cellular&utm_term=4581115212136357&utm_content=BING_SmartShopping_Romans%26Cellular

I love these blue Botanicals in a gallery for that wall.

https://www.ballarddesigns.com/bd/674565?slid=0eeacd25-f3f1-46b8-bfb7-85d787f76082&CAWELAID=120245430001046940&cjevent=c6f40b931c6911ee81083ba90a1eba24&SourceCode=AFF7412067&utm_source=Stylight+Inc.&utm_medium=Affiliates&utm_campaign=default&cjdata=MXxOfDB8WXww

Nice glass centerpiece or tablescape:

Glam Blue Glass Vase 560201 · More Info