I think that the two following tool (from the processing toolbox) may help you to do what you want,
The first one help only if your bend are true curve (not likely to really help you).
The second by extracting vertices and adding a field for the bisector angle at the position of vertice that should do exactly what you want (It seem that the angle value on point is average angle of lines before and after vertex. First point has no "before line" so its actual angle of line after vertex. Last point has no "after line" so its actual angle of line before vertex. Angle are in degrees clockwise from north to line geometry)
Segmentize by maximum angle
This algorithm segmentizes a geometry by converting curved sections to
linear sections. The segmentization is performed by specifying the
maximum allowed radius angle between vertices on the straightened
geometry (e.g the angle of the arc created from the original arc
center to consecutive output vertices on the linearized geometry).
Non-curved geometries will be retained without change.
This algorithm takes a line or polygon layer and generates a point
layer with points representing the vertices in the input lines or
polygons. The attributes associated to each point are the same ones
associated to the line or polygon that the point belongs to.
Additional fields are added to the point indicating the vertex index
(beginning at 0), the vertex’s part and its index within the part (as
well as its ring for polygons), distance along original geometry and
bisector angle of vertex for original geometry.