Theoretical question Eloquent Builder and MySQL

I creation product properties table. At first glance, this is a very simple task. "Product prorepty" table structure like this

$table->id();
$table->unsignedBigInteger('product_id');
$table->string('key');
$table->text('value');

No problems, but we want query by property. No problem too. like this:

Product::whereHas('property', function($query) {
	$query->where('key', 'color');
	$query->where('value', 'blue');
})->get()

BUT! If I want to query it by numeric value something like

->where('weight', '>', '1000')

table column has text or string type, but I want to use it like it is integer or double... Laravel Metable package: https://github.com/plank/laravel-metable fix it by cast field as decimal

$q->whereHas('meta', function (Builder $q) use ($key, $operator, $value, $field) {
            $q->where('key', $key);
            $q->whereRaw("cast({$field} as decimal) {$operator} ?", [(float)$value]);
        });

And finaly my question is:

1. With this approach like laravel-metable do, how about query processing speed?
2. In my ecommerce progect it will be many many queries by property, and processing speed is important, and maybe I should create table with few colums for every type and query by specific column like this ?:

$table->id();
$table->unsignedBigInteger('product_id');
$table->string('key');
$table->integer('int_value');
$table->text('string_value');
$table->double('double_value');

Can anybody say something about query processing speed in the case I described ?