It might be the way your photo is taken, but it looks a decent length, so grass + boarder might look a bit long and boring. I would think of something placed in the last 3rd to break it up visually. As it's on a slope the obvious thing would be to terrace the lawn.
Also have a think about where you're ultimately going to want to sit/hangout when the weather is nice.
. 2. If you want really long term you want
jarrah sleepers. Oak should still last a long time ~15yrs iirc.
https://www.railwaysleepers.com/used-railway-sleepers/used-g1-2-jarrah-tropical-hardwood-railway-sleepers
It might be the way your photo is taken, but it looks a decent length, so grass + boarder might look a bit long and boring. I would think of something placed in the last 3rd to break it up visually. As it's on a slope the obvious thing would be to terrace the lawn.
Also have a think about where you're ultimately going to want to sit/hangout when the weather is nice.