how to rotate my character along the y axis when character is aligned with a slope

Question

I have a capulse character Im moving around in my 3d Game, I usually rotate the character using this line of code:

void HandleRotation(){
        if(_move.magnitude > 0.1){
            _targetAngle = Mathf.Atan2(_move.x, _move.y) * Mathf.Rad2Deg + _camera.transform.eulerAngles.y;
            angle = Mathf.SmoothDampAngle(_playerTransform.eulerAngles.y, _targetAngle, ref _turnSmoothVelocity, 0.02f);
            Vector3 relativeForce = (Quaternion.Euler(0f, _targetAngle, 0f) * Vector3.forward).normalized;

                publisher.UpdateDirection(_move);
                _force.x = relativeForce.x * Speed * _move.magnitude;
                _force.z = relativeForce.z * Speed * _move.magnitude;
            
        }
        else {
            _force.x = 0;
            _force.z = 0;
            publisher.UpdateDirection(new Vector2());
        }
    }

 void ApplyRotation(){

      _rigidbody.MoveRotation(Quaternion.Euler(0, angle , 0));
 }

This works fine when on a flat plane, and on slopes, however id like to align my player to the slope they're on. I have code to check if a player is on a slope and to align them to the slope:

void SlopeCheck()
    {
        Quaternion newRot;
        RaycastHit downHit;
        if (Physics.Raycast(_groundCheck.position + Vector3.up, Vector3.down, out downHit, 5f, _groundLayer) && _isGrounded && !_jumpPressed)
        {
            _onSlope = true;
            slopeNormal = downHit.normal;
            _playerTransform.rotation = (Quaternion.FromToRotation(_playerTransform.rotation.eulerAngles.normalized, slopeNormal)) * _playerTransform.rotation;
        }
    }

However this ends up making my character jitter like crazy along the x axis:

I have tried combining these two rotations in various ways but each one gives me awkward results, is there a way for me to make sure I can still rotate my character along the Y axis when aligned along a slope? I'm guessing because my character isnt pointing directly upwards, the rotation would need to be some combination of an x,y,z rotation but I'm unsure how to derive this in code. Any help would be greatly appreciated!

Answer 1

It seems like this order of rotation did the trick for me:

_playerTransform.rotation = (Quaternion.FromToRotation(Vector3.up, slopeNormal)) * (Quaternion.Euler(0, angle , 0));

It also works using MoveRotation!