How to wallpaper this wall?

[m3jappa]

We want to wallpaper this wall, it has an arch in it, I don't want it to go into the arch into the other side iykwim.

Yes I can see I could try and cut it to the arch shape but I can imagine the edges aren't perfect and I can also imagine it peeling away.

Any ideas? I thought maybe a piece of flexible Ali trim. It I can't seem to find anything which doesn't fit under tiles.