A big neutral rug (not multiple colors like you have), a console table under the cut out arch, and a mirror above it.

Beautiful space! I like the first picture with the rug horizontal by the door, makes the most sense for functionality and looks nice too. I think it matches very nicely... I don't like the art work in that arch way...I feel like something smaller should go in there and that piece should have its own wall.. Room can be filled in with a plant, small console table... I think a plant would add some greenery/life and help with the pop you're looking for

asba... suggestion for artwork in the archway?

i am really not sure but i think the straight edge of the picture really clashes with the arch... maybe something round or a unique rounded shape ... maybe metal type? Im stumped!

Maybe a pro can make a suggestion...

I like the art in the niche, but hang it - don't lean it. We have four similar niches in our foyer, each displaying a large format canvas painting sized like yours. Makes a good impact. I also like the rug horizontally, as in the first pic, but think the rug fights with the abstract painting. If it were my space, I'd look for a different rug.

then maybe you can fill the top of the arch with a painting lamp so it doesn't leave that empty gap

https://www.amazon.com/Rite-Lite-LPL601XLBRC-Battery-Operated/dp/B005FLVIW8/ref=sr_1_29?dchild=1&keywords=artwork+light&qid=1597678842&sr=8-29

I was thinking that or a small decorative iron piece to fill the space. yes it will be hung I just have that leaning till I figure out exactly what painting will go where. when in the house, and the rug is over by the front door and not right underneath the painting they don't seem to compete as much as they do in the picture. should I get a little smaller version of this picture or is this size with a decorative piece above in the arch part fine?

got a good idea about what to do with the entry now my dining room. a previous post.

I wouldn't do a decorative iron piece above the picture. I think they detract from artwork and just create visual clutter. The size of your art piece is fine, and you don't need to do anything to fill the arch.