Navmesh or terrain axis swap from XZ to XY?

Hi,

I am working on a game similar to a shoot em up. Player and Enemies are supposed to move and fight on a a 2D plane, which is defined by a Navmesh. That makes it possible for me to bend said "gameplay plane" around a bit to make everything feel more dynamic.

BUT Navmesh and it's Agents only work on the XZ axis, so in order to make this possible I would have to rotate the entire scene to put the gameplay plane on the XZ axis.

BUT...if i do that, I won't be able to use the Terrain system anymore because it would face into the wrong direction. Because that is locked to the XZ axis as well and terrains cannot be rotated either, as far as i know.

At this rate i will have to give up using either the terrain or the pathfinding system of unity (I have the pro version) entirely.

So are there any known ways or third party solutions to make either terrain or navmeshes/pathfinding work on the XY plane instead?