WitShop/app/Models/ProductVariant.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;

class ProductVariant extends Model
{
    protected $fillable = ['product_id','sku','price_override','stock','stock_warning','active'];

    protected $casts = ['active' => 'boolean', 'price_override' => 'decimal:2'];

    public function product(): BelongsTo
    {
        return $this->belongsTo(Product::class);
    }

    public function attributeValues(): BelongsToMany
    {
        return $this->belongsToMany(AttributeValue::class, 'product_variant_attribute_values')
            ->with('attribute');
    }

    public function getEffectivePriceAttribute(): float
    {
        return (float) ($this->price_override ?? $this->product->base_price);
    }

    public function getLabelAttribute(): string
    {
        return $this->attributeValues->map(fn($v) => $v->value)->join(', ');
    }
}