I recently picked up these 2. One from:
Amazon- https://www.amazon.com/gp/product/B08586CVVV/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
and one from
Both work fine. The Mophie from Amazon has a open USB slot to plug in any watch charging dock or cable. And the one from ebay has a dedicated watch compatible dock for samsung watches. The only cons are the both will only charge the phone at a max 10w instead of 15w