Magento 2: Load product data-block (via webservice) on product page

Question

We use Magento 2.3.

We should be able to load a data block (containing a message related to the speed of delivery) on the product page.

The message should be loaded real time as it depends on the current stock of the SKU in 2 external databases. We need to call a web service (sku is the parameter) and the webservice returns a message that we need to display on the product page.

Or in other words: we want to show a product attribute where the value is retrieved on the fly (instead of prefixed in the database)

How can this be achieved? Do we need to be afraid of performance slow down (possible in lazyload)?

Br Mike

PS: We also use configuables so this might be an extra complexity.