murph-core/src/core/Entity/Site/Page/CollectionBlock.php

<?php

namespace App\Core\Entity\Site\Page;

use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity]
class CollectionBlock extends Block
{
    public function getValue()
    {
        return json_decode(parent::getValue(), true);
    }

    public function setValue($value): self
    {
        return parent::setValue(json_encode($value));
    }
}