I don’t have a complete answer for you, just some idea after doing a quick 5 minute search.
First you would need to use something like a post object field to select the product.
The next step would be to create a select field. This field needs to be populated dynamically based on the selection in the first field. Do a search for “ACF dynamically populate a field from another field” in google and you will find this question comes up often.
You will need to do a custom query to get the product variations to populate the second field. These are saved as the post type “product_variation” with the “post_parent” value set to the “product” post of the main product.
To display this you’d need to figure out how to link to a specific product variation based on the values of these two fields.
