PlayerMovement.cs

using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;

public class PlayerMovement : MonoBehaviour
{
    private Rigidbody _body;

    private PlayerInputController _inputController;

    [SerializeField]
    private PlayerConfigModule _playerConfig;

    // Start is called before the first frame update
    void Start()
    {
        _body = GetComponent<Rigidbody>();
        _inputController = GetComponent<PlayerInputController>();
    }

    void FixedUpdate()
    {
        var currentDirection = _inputController.GetRequestedDirection();

        if (currentDirection != Direction.None) {
            var position = new Vector3(0, 1, 0);
            var vector = GetMovementVector(currentDirection);

            // we apply only one of stationary boost, reverse boost or turn boost, favoring them in that order
            if (_playerConfig.StationaryBoost > 0 && !IsMoving()) {
                _body.AddForceAtPosition(_playerConfig.StationaryBoost * vector, position, ForceMode.Impulse);
            } else if (_playerConfig.ReverseBoost > 0 && _inputController.IsReversed()) {
                _body.AddForceAtPosition(_playerConfig.ReverseBoost * vector, position, ForceMode.Impulse);
            } else if (_playerConfig.TurnBoost > 0 && _inputController.IsTurned()) {
                _body.AddForceAtPosition(_playerConfig.TurnBoost * vector, position, ForceMode.Impulse);
            }

            _body.AddForceAtPosition(_playerConfig.ContinuousForce * vector, position, ForceMode.Force);
        }
    }

    // uses the player config's "stationary threshold" to determine if the player is moving
    private bool IsMoving()
    {
        return _body.velocity.magnitude >= _playerConfig.StationaryThreshold;
    }

    // calculate the movement vector for the given direction
    private Vector3 GetMovementVector(Direction direction)
    {
        var vector = direction switch {
            Direction.East => new Vector3(1, 0, 0),
            Direction.Northeast => new Vector3(1, 0, 1),
            Direction.North => new Vector3(0, 0, 1),
            Direction.Northwest => new Vector3(-1, 0, 1),
            Direction.West => new Vector3(-1, 0, 0),
            Direction.Southwest => new Vector3(-1, 0, -1),
            Direction.South => new Vector3(0, 0, -1),
            Direction.Southeast => new Vector3(1, 0, -1),
            _ => Vector3.zero,
        };

        var mapRotation = Camera.main.transform.eulerAngles.y;
        return mapRotation == 0 ? vector : Quaternion.AngleAxis(mapRotation, Vector3.up) * vector;
    }
}