Various maps can already be generated with a Terrain Color operator. You can save them into whatever channel name you like (doesn't have to be "color") and then export with an Export Terrain operator.
As for UDIMs...I have a cursory undersanding of them but have never used them myself. Isn't it something that's typically setup after terrain is generated/exported? You can use the Terrain Tile operator to subdivide a single tile into more tiles (example, a single 8k tile into 5x5 8k tiles), and then export all those individual tiles to various texmaps after you apply whatever FX/colors you want to them. Then UDIMs would be used to load those maps onto a single mesh afterwards, no? I guess I could add settings in the Terrain Mesh operator to prep meshes with UDIM-compatible UVWs. Any other features you'd like to see added in that area?
As for UDIMs...I have a cursory undersanding of them but have never used them myself. Isn't it something that's typically setup after terrain is generated/exported? You can use the Terrain Tile operator to subdivide a single tile into more tiles (example, a single 8k tile into 5x5 8k tiles), and then export all those individual tiles to various texmaps after you apply whatever FX/colors you want to them. Then UDIMs would be used to load those maps onto a single mesh afterwards, no? I guess I could add settings in the Terrain Mesh operator to prep meshes with UDIM-compatible UVWs. Any other features you'd like to see added in that area?