Not every wall needs to be decorated. You could easily put a large tall plant in the corner next to the window. Home Depot usually has good ones for not too much. Any of these would work well. Every room needs a plant. They're great space fillers without looking contrived. They really cozy up a room.

I came up with an idea about an hour after I posted, but unfortunately Houzz won't let me delete or edit this post. I hesitate to do a runner here. It's fairly high traffic from the mudroom and I generally stay away from rugs (if there's an eensy teensy corner sticking up, I'll trip on it). But for the wall itself, I decided to take some black and white photos of landmarks around where I live and frame them. I have a couple usable pictures, and will go out and get some more (and better) shots. I'm not a professional photographer, but have taken a few courses and can get good shots for this purpose. Patricia, we have a long hall in our basement too, and that's probably where I'll do a few framed posters and family photos.

Beautiful entry. You really don't need anything in it other than a good no slip rug (and no stub/stumble edges). You could keep a small square or rectangle wipe-your-feet-rug and then in area between the cased openings consider adding an interesting round or oval or square one with your favorite colors (also non slip and with no stub/stumble edges). Prefer seeing the radiators. For decor, you don't "need" that shelving; it's higher than the wainscoting and both of them likely could be put to better use elsewhere. Were you using the shelving as a charging station or place to "drop" keys and sunglasses, etc.? because, if so, there is another option that might could work in your limited space -- perhaps a small narrow version of this on the wall. https://www.wayfair.com/Zipcode-Design%E2%84%A2--Jon-Floating-Desk-X115392267-L32-K~W004281156.html?refid=GX528945860062-W004281156_624721285&device=c&ptid=998723531694&network=g&targetid=pla-998723531694&channel=GooglePLA&ireid=130981889&fdid=1817&PiID%5B%5D=624721285&gclid=EAIaIQobChMIiarSip278gIVhrzICh1o1w3gEAkYASABEgJU8vD_BwE OR. You could block the view of the end of the radiator from inside the house by adding a pair of small narrow cabinets the same height and depth as the radiators on the indoor side of the entry -- a plant stand cabinet (permitting you to add a living plant or two to the entry) and with at least one drawer that could serve as a charging station (and more drawer or have shelves for baskets for collecting other pocket items). Any cabinet you like that meets your needs could serve the purpose, preferably one portable enough to easily move farther away from the radiator when it is in use: https://www.amazon.com/Cabinet-Bathroom-Multifunctional-Standing-EstaHome/dp/B087QK889H https://foter.com/plant-stand-with-drawer https://www.amazon.com/VIAGDO-Bathroom-Floor-Cabinet-Organizer/dp/B082HWNWV8/ref=pd_lpo_3?pd_rd_i=B082HWNWV8&psc=1 https://www.amazon.com/Stands-Multi-Layer-Drawers-Display-Minimalist/dp/B082H88BSC.

I now have a very fancy laundry room with a wool rug. The runner looks very good in my second floor laundry. Here's a pic of the entry space without the rug. I'm now looking for suggestions for another rug. I can't go too light because I'll be coming in from the garage, but I would like something nice and soft to step on.