How to map texture to landscapes 0-1 UV coordinates, no tiling

That’s an Assumption. With a real emphasis on the first 3 letters part…
Landscapes change from level to level. What works in one level probably won’t work in another.

Object Position > Mask RG > Subtract A
Object Bounds > Mask RG > Subtract B
→ Result into > a new Subtract B

Absolute WP > Mask RG > the new Subtract A
→ Result into > Divide A

From: Object Bounds > Mask RG > Multiply * 2 > Into Divide B.

End result is a UV that will always cover any landscape of any size. Or any object for that matter - in X/Y directions.