When I'm using second operator right after the first, it undo the first operator result

Question

There's my first operator, it do many things but you have to know, that it does makes vertex group "Heel".

class HEEL_OT_cut_heel(bpy.types.Operator):
    """Go to -Z pointview, then select scan object and press this button to create a heel."""
    bl_label = "Cut heel"
    bl_idname = "mesh.cut_heel_operator"
    
    @classmethod
    def poll(cls, context):
        return context.active_object is not None
    
    def execute(self, context):
    
    ...

    group_heel = cut_and_clean(scan, curve)
    group_heel.name = 'Heel'

    ...

    return {'FINISHED'}

There's my second operator:

class HEEL_OT_elongate_heel(bpy.types.Operator):
    """If scan have hell vertex group, press this button to enlongate it"""
    bl_label = 'Elongate heel'
    bl_idname = 'mesh.elongate_heel_operator'
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        return context.active_object is not None

    transition_value: bpy.props.FloatProperty(
        default = 15,
        soft_min = 10,
        soft_max = 25
    )

    def get_transition_value(self):
        return self.transition_value

    def set_transition_value(self, x):
        self.transition_value = x

    def invoke(self, context, event):
        self.set_transition_value(bpy.context.scene.heel_transition_value)

        return self.execute(context)

    def execute(self, context):
        scan = bpy.context.active_object

        if scan.mode != 'OBJECT':
            bpy.ops.object.mode_set(mode = 'OBJECT')

        if validation_scan(scan):
            self.report({'ERROR'}, "Object is not configurated.")
            return {'CANCELLED'}
        
        group_heel = scan.vertex_groups.get("Heel")
        if not group_heel:
            self.report({'ERROR'}, "Object don't have 'Heel' vertex group.")
            return {'CANCELLED'}

        select_vertex_group(scan, group_heel)
        bpy.ops.object.mode_set(mode = 'EDIT')
        # Scale to cursor 
        bpy.context.scene.cursor.location[2] = get_min_z(scan)
        bpy.context.scene.tool_settings.transform_pivot_point = 'CURSOR'
        
        bpy.ops.object.mode_set(mode = 'EDIT')  

        bpy.ops.transform.resize(
            value=(1, 1, 0), 
            orient_type='GLOBAL',
            orient_matrix_type='GLOBAL', 
            constraint_axis=(True, True, True), 
            mirror=True, 
            use_proportional_edit=True, 
            proportional_edit_falloff='SHARP', 
            proportional_size = self.get_transition_value(), 
            use_proportional_connected=True
        )

        bpy.ops.object.mode_set(mode = 'OBJECT')

        bpy.context.scene.heel_transition_value = self.get_transition_value()
        return {'FINISHED'}

When I use first operator on active object and then without other action (move, scale, etc.) I use second operator, it do take those both actions as one. This is how I do understand this. When I try to undo it with Ctrl + Z shortcut, then I get back before vertex group "Heel" has been assigned. And when I try change transition_value in Redo Panel, second operator also didn't get vertex group "Heel", because it wasn't there.

I'm still learning Blender library, so if you see something ugly in my code, please, let me know.