The auto-populated SKU for a duplicated product in Magento 2.4.5 is a new feature called "Duplicate SKU Increment". This feature is designed to prevent unintentional overwriting of existing products with the same SKU.
By default, when a product is duplicated, Magento will append "-1" to the SKU of the duplicated product. If you duplicate the same product again, the SKU will be incremented to "-2", and so on.
If you want to change the auto-populated SKU, you can do so by modifying the configuration settings. Here are the steps to follow:
Log in to your Magento admin panel.
Go to Stores > Configuration > Catalog > Catalog.
Expand the Product Fields Auto-Generation section.
Find the Duplicate SKU Increment field and change the value to the desired increment, or set it to 0 to disable auto-increment altogether.
Save the configuration.
Once you have made this change, the auto-populated SKU for duplicated products will reflect the new increment value you have set.
Note that changing this configuration setting will affect all duplicated products going forward, so make sure you choose an increment value that works for your specific use case.