2D Terrain / Paint on (plane)-mesh

Hi, i would like to use the terrain in the 2D space of unity, however this doesn't seem to be possible, since neither the terrain nor 2D-colliders can be be rotated and flipping the terrain in the settings is also not possible.

Since i would mainly use the terrain engine for graphics & the placement utility function and those features could mostly be handle through gameobjects, i can kind of work around the issues, but especially painting textures on meshes (similar to the paint texture option for terrains) as well as the general option to paint gameobjects like trees or other details would still be very helpful.

Worst case i could write own code, but it would still help to get access to the unity brushes to draw in the editor window, however i couldn't find any documentation about those, since most search results were about the terrain editor or drawing on textures at run time.

Basically:

• are there any 2D-Terrain addons/scripts?

• if not: are there options to paint on meshs and place gameobjects?

• if not: can we access the brush/paint-api of the terrain editor (or anything similar)?

Thanks.