How to Auto Select Size Attribute [Multi Sizes] in Magento 2.4.6

[khaledmoha8b45]

I'm using Magento 2.4.6, and I need to show the product view page by three different attributes (SizeEuro,SizeRegular, and SizeUS) for configurable products. I created the multi-size attributes for that specific product like below:

attributes img 

When the user selects any of the attributes, another attribute strikes out automatically and is shown in the appropriate size. Now my issue is that when the user clicks the Add to Cart button, a validation error occurs (the field is required), as shown here:

 Product Page Img 

So the user is forced to select each size attribute manually, one by one.

I just need to make the attribute select automatically when the user selects any one of the size attributes.

[toniagency82ed]

We can't see the attached images here (a bug in Adobe Commerce forums I guess), but can't you make the attribute values contain all 3 sizes?

Like "US 7 / Regular S / UK 37" being just 1 value of the Size attribute?

[khaledmoha8b45]

I updated the image links and it's three different attributes.

[toniagency82ed]

Exactly as I said, you made it vary by 3 different attributes while in reality they vary by just 1 size attribute.

So instead of this you should have 1 size attribute and values of this attribute should contain the value in all 3 systems.

So instead of having SizeEuro, SizeRegular, and SizeUS attributes that each hold their own values you should have just 1 "Size" attribute. And in values of this size attribute write down all 3 versions like "Euro size: 38 / Size: 12 / US size: 1" as one value of the size attribute.