Nobody has any ideas? :)

To retrieve all three relationships (ModelA, ModelB, ModelC) for a User in Laravel using Eloquent's morphMany relationship, you can define custom methods in your User model. Here is an example: In your User model, define the morphMany relationships for ModelA, ModelB, and ModelC:

class User extends Model
{
    // ...

    public function modelA()
    {
        return $this->morphMany(ModelA::class, 'user');
    }

    public function modelB()
    {
        return $this->morphMany(ModelB::class, 'user');
    }

    public function modelC()
    {
        return $this->morphMany(ModelC::class, 'user');
    }

    // ...
}```

Next, create a custom method in the User model to retrieve all the models at once:

```use Illuminate\Database\Eloquent\Model

class User extends Model
{
    // ...

    public function allModels()
    {
        return $this->modelA->concat($this->modelB)->concat($this->modelC); 
    }

    // ...
}

Now, you can use $user->allModels to retrieve all the related models for a user.

Thanks for the reply. This is my code but doesn't seem to work.

public function devices_digital_matter(){
        return $this->belongsToMany(Device::class,env('DB_DIGITAL_MATTER_DATABASE').'.device_user');
    }
public function mobile_devices(){
        return $this->hasMany(\App\Models\Integration\Mobile\Device::class);
    }
public function all_devices(){
        return $this->mobile_devices->concat($this->devices_digital_matter);
    }

Am i missing something? The error is App\Models\User::all_devices must return a relationship instance

Got it, needed $user->all_devices() not $user->all_devices