This is an accepted solution.
Hank here from Shopify!
While you are able to embed the youtube video into the product description using the rich text editor, it is not possible to embed it into an image and then into the description natively within the Shopify admin, but don't worry there are other ways this can be done!
The first way would be through the likes of a page builder app, which would allow you to create a custom page, allowing you to create custom pages, with different workflows and options.
Then another option would be that hopefully, someone with more technical skills in the community will come across this and be able to add some value to you here, but if not, your best bet might be to reach out to one of our Shopify Experts, who you can hire to do almost any custom work on your store.
If you were to reach out to them about this query, they would be able to resolve this issue for you as they could make the relevant edits to the product code for you.
All the best,