Delete curve lines

Sounds like a job for the AngularityCalculator.

No unfortunately. Show straight line like 0 and sometimes curves with 0 too...😭

I suspect it has to do with the data. You can share a FFS if you want me to try.

From the documentation:

Calculates the "angularity" of a linear or area feature. Angularity indicates the degree of curvature of a feature. The higher the value, the more curved its geometry.

A value of 0 indicates the geometry is a straight line. This mode works on linear and polygonal geometries, and all other geometries will receive a value of 0.

The calculation of this property utilizes the angle between segments and, as a result, linear and polygonal features must have more than one segment to receive a non-zero value. Arcs are stroked into lines before determining this value. The actual value is the sum of the angles between the segments divided by the total length of the segments.