Specific RelationManager does not show

public static function getRelations(): array
{
    return [
        RelationManagers\ServicesRelationManager::class,
        RelationManagers\PassengerRelationManager::class, // Not visible
        RelationManagers\VehicleRelationManager::class,
        RelationManagers\PaymentsRelationManager::class,
    ];
}

/**
 * @var array<int, string>
 */
protected $fillable = [
    'passenger_id',
    // ...
];

public function passenger(): BelongsTo
{
    return $this->belongsTo(
        related: PassengerInfo::class,
        foreignKey: 'passenger_id',
        ownerKey: 'id',
    );
}

// OR

public function passenger(): HasOne
{
    return $this->hasOne(
        related: PassengerInfo::class,
        foreignKey: 'id',
        localKey: 'passenger_id',
    );
}

// EVEN

public function passenger(): HasMany
{
    return $this->hasMany(
        related: PassengerInfo::class,
        foreignKey: 'id',
        localKey: 'passenger_id',
    );
}