Improvement of complex Eloquent Query

I have some code which queries a database on which i don't have any control (i can't change the structure or anything). In this database there is table created for every campaign in the campaigns table. To hold the history. I need to query this history tables to get the results and monitor some employees. The following code works, but i don't like it. Do you guys have any improvements?

// Some validation before..

$date_from = Carbon::parse(request('date_from'))->startOfDay();
$date_to   = Carbon::parse(request('date_to'))->endOfDay();

$department_id = request('department_id');

$campaigns = Campaign::query()
	->where('is_active', 1)
	->select('PID', 'name', 'is_active')
	->get();

$employees = Employee::where('department_id', $department_id)
	->where('is_active', 1)
	->where('funktie', Functie::TELEMARKETEER)
	->select('PID', 'department_id', 'is_active', 'function', 'friendlyname', 'fullname', 'listname', 'lastlogin', 'name', 'firstname')
	->whereHas('workdays', function ($query) use ($date_to, $date_from) {
		return $query->where('workday_datefrom', '>=', $date_from)
			->where('workday_dateto', '<=', $date_to);
	})
	->with([
		'workdays' => function ($query) use ($date_to, $date_from) {
			return $query->where('workday_datefrom', '>=', $date_from)
				->where('workday_dateto', '<=', $date_to);
		},
		'workdays.breaks'
	])
	->get()
	->keyBy('PID');

// This is the main part i don't like... 
$history = $campaigns->keyBy('PID')->map(function ($campaign) use ($employees) {
	return DB::connection('cdra')
		->table(sprintf("C%'.06d_History", $campaign->PID)) // Looks like C000085_History for example
		->whereIn('workday_pid', $employees->pluck('workdays.*.PID')->flatten()->unique()->toArray())
		->whereIn('employee_pid', $employees->pluck('PID')->toArray())
		->get();
})->flatten();

$employees = $employees->map(function ($employee) use ($history) {
	$employee->history = $history->where('employee_pid', $employee->PID)->toArray();
	
	return $employee;
});			


// Do something with this data after.. 

I don't really want to create models for each of the campaign_history tables because campaigns could be added and i don't want to change the code if that happens..

If there's any way to query all the history tables at once, or make one model to use for al it would be great.. Any suggestions are welcome!