Sort results in Laravel by table from the relationship

I am beginner in Laravel. I use in my project Laravel 5.8.

I have user:

Schema::create('users', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->char('enable', 1)->default(0);
            $table->string('name', 120)->nullable();
            $table->string('surname', 120)->nullable();
            $table->string('email', 120)->unique();
            $table->timestamp('email_verified_at')->nullable();
            $table->string('password');
            $table->dateTime('last_activity')->nullable();
            $table->rememberToken();
            $table->timestamps();
            $table->engine = "InnoDB";
            $table->charset = 'utf8mb4';
            $table->collation = 'utf8mb4_unicode_ci';
        });


class User extends Authenticatable implements MustVerifyEmail
{
    use Notifiable;
    use psCMS\Presenters\UserPresenter;
    use scopeActiveTrait;

    public static $roles = [];
    public $dates = ['last_activity'];

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */

    protected $fillable = ['enable', 'name', 'surname', 'email', 'email_verified_at', 'password' 'remember_token', 'created_at', 'updated_at', 'last_login_at', 'last_login_ip'];


    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */

    protected $hidden = [
        'password', 'remember_token',
    ];

    public function comments()
    {
        return $this->hasMany('App\Comment');
    }

    public function userCommentsCount()
    {
        return $this->hasMany('App\Comment', 'commentable_id', 'id')->where('enable', '=', '1')->where('to_stats', '=', '0');
    }

public function scopeUserAvailable($query)
    {
        return $query->active()
            ->where('email_verified_at', '<>', null);
    }


}

and comments:

Schema::create('comments', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->bigInteger('user_id')->unsigned();
            $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
            $table->string('commentable_type');
            $table->bigInteger('commentable_id');
            $table->char('enable', 1)->default(0);
            $table->char('to_stats', 1)->default(0);
            $table->tinyInteger('rating')->default(0);
            $table->text('content');
            $table->dateTime('date_time');
            $table->ipAddress('ip');
            $table->engine = "InnoDB";
            $table->charset = 'utf8mb4';
            $table->collation = 'utf8mb4_unicode_ci';

        });

class Comment extends Model
{

    use scopeActiveTrait;

    protected $quarded = ['id'];
    protected $fillable = ['content', 'enable', 'rating', 'user_id', 'commentable_type', 'commentable_id', 'date_time', 'ip'];
    public $timestamps = false;

    public function commentable()
    {
        return $this->morphTo(); 
    }

    public function user()
    {
        return $this->belongsTo('App\User');
    }
}

In the comments table I have "rating" (values from 1 to 5).

I have user list:

$role = [];
        if ($userType == 1) {
            $role = ['UserNormal'];
        } elseif ($userType == 2) {
            $role = ['UserPremium'];
        }

        return User::ofRoleType($role)
            ->where(function ($q) use ($query, $sortColumn, $sortMethod) {
                $q->userAvailable()
                    ->orderBy($sortColumn, $sortMethod);
            })->orderBy('id', 'ASC)->paginate(15);

How can I sort by: a) the number of comments per user (the user has many comments) b) the size of votes cast in the rating (each user has many comments and many different votes)

??

How can I make it?

via Chebli Mohamed