Size Chart Not Showing Except in the Product Tab

I tried adding the size chart button using after title, but not working. The only option working is product tab. The after title is not showing.
Also, the one you mentioned in here, the option is not there at all where we can add between variation and add to cart button.
https://snipboard.io/nDJbUm.jpg – I got this from the forum.

You may check this product as it has the size chart assigned.
https://aidanglobal.com/product/dark-knight-race-fit-cycling-jersey/

So the button for size chart is not showing is the issue.