<?php

function getColors($item_colors, $result = []){
    preg_match_all('/(\w+),|(\w+)\/(\w+)/', $item_colors, $colors);
    foreach ($colors as $key => $value) {
        if ($key === 0) continue;
        array_push($result, ...$value);
    }
    return array_filter($result);
}


$item_colors = "Vario Base Unit with steel, large, black/orange";

echo implode(' ', getColors($item_colors));
//steel large black orange

var_dump(getColors($item_colors));
// array(4) {
//   [0]=>
//   string(5) "steel"
//   [1]=>
//   string(5) "large"
//   [5]=>
//   string(5) "black"
//   [8]=>
//   string(6) "orange"
// }

<?php

$item_colors = "Vario Base Unit with steel, large, black/orange";

$result = [];
foreach (explode(', ', str_replace('Vario Base Unit with ','', $item_colors)) as $color) {
    $colors = explode('/', $color);
    count($colors) === 2 ? array_push($result, ...$colors) : array_push($result, $color);
}



echo implode(' ', $result);
//steel large black orange

var_dump($result);
// array(4) {
//   [0]=>
//   string(5) "steel"
//   [1]=>
//   string(5) "large"
//   [2]=>
//   string(5) "black"
//   [3]=>
//   string(6) "orange"
// }

<?php

$item_colors = "Vario Base Unit with steel, large, black/orange";

$result = eval('return '.str_replace(['Vario Base Unit with ', '/', ', '], ['["',', ', '", "'], $item_colors).'"];');

echo implode(' ', $result);
//steel large black orange

var_dump($result);
// array(4) {
//   [0]=>
//   string(5) "steel"
//   [1]=>
//   string(5) "large"
//   [2]=>
//   string(5) "black"
//   [3]=>
//   string(6) "orange"
// }

<?php

class KeysReplacer {
    public $default = [
        'id' => 'id',
        'full_address' => 'adress',
        'floorall' => 'floorall',
        'build_year' => 'build_year',
    ];

    public $services = [
        'service_1' => [
            'id' => 'internal_id',
            'full_address' => 'locality',
            'floorall' => 'floorall',
            'build_year' => 'build_date'
        ],
        'service_2' => [
            'id' => 'ид',
            'full_address' => 'полный_адрес',
            'floorall' => 'этажность',
            'build_year' => 'год_постройки'
        ],
    ];
    
    
    public function __invoke($item, $from = null)
    {
       $result = [];
            foreach($item as $key => $value){
                $result[$from && isset($this->services[$from][$key])
                ? $this->services[$from][$key]
                : $this->default[$key]] = $value;
            }
        return json_encode($result, JSON_UNESCAPED_UNICODE);
    }

}



function getItem(){
    return [
        'id' => 1,
        'full_address' => 'г. Москва',
        'floorall' => 18,
        'build_year' => 1990
    ];
}



$item = getItem();

$responseNormalizer = new KeysReplacer;

$response_0 = $responseNormalizer($item);
$response_1 = $responseNormalizer($item, 'service_1');
$response_2 = $responseNormalizer($item, 'service_2');

var_dump($response_0); // string(68) "{"id":1,"adress":"г. Москва","floorall":18,"build_year":1990}"
var_dump($response_1); // string(79) "{"internal_id":1,"locality":"г. Москва","floorall":18,"build_date":1990}"
var_dump($response_2); // string(112) "{"ид":1,"полный_адрес":"г. Москва","этажность":18,"год_постройки":1990}"