Triplaner shaders are are awesome for mesh terrains and can also stop the stretching. This “Terrain vs Mesh” thread is an awesome resource regarding very quantifiable performance improvements by using mesh terrains certain ways. It especially delves into open world optimization in detail while being pretty concise considering the subject matter. Lots of really good objective questions, answers, findings, and battle tested strategies on the subject.
There’s also many existing solutions that address stretching on traditional terrains as another user mentioned.