Try a small Oriental rug with some brown in it. Tape out 3 by 5 feet and 2 by 4 feet to see which size fits best. There are also rugs in sizes in between.

I'd put a small (2x3-ish) Waterhog mat just inside the door to catch any wet footprints. You'll want something non-slip where people enter. Looks like you have space to add a runner down the hallway to the left of the stairs.

I would put the waterhog outside at the door and then a small mat inside that absrobs water but can be washed easily. A solid color for sure and maybe just almost a match to the floor color. It looks like it can’t be too thick either . This is a from a company called magic doormts you might want to check them out.