The Galaxy M51 has finally been confirmed as a smartphone that is soon to be released. It is now avaialble to pre-order, albeit only via Samsung's German website. However, it is also currently being teased on Amazon India, suggesting that it will launch very soon on that platform. One of its new campaigns confirm the phone's 7000mAh battery spec.
https://www.notebookcheck.net/The-Galaxy-M51-is-now-up-for-pre-order-on-Samsung-Germany-s-website.490819.0.html