Hello,
1. Please make sure that you have to enable “Manage stock” in the product, fill the “Stock quantity” field out, and insert the initial quantity. https://ibb.co/nrLHM2L
For more details please read the below article:
https://xtemos.com/docs-topic/products-stock-progress-bar/
2. There is no settings available for the title and wishlist icon to align but kindly, please share your Site WP-ADMIN Login details in the Private Content field so that we can check this concern on your Site and help you out accordingly.
3. What do you want to setup for display differences on different devices? I did not understand your requirements.
Best Regards.