I was running through some adverts on a mobile game and an ad came up which WAS Sea of Thieves game footage. Zero doubt about it.
It's a game called "Tides of Treasure (Early Access)" by Puzala. Seems that it's in development, which is obvious I guess since the game title has Early Access in it.
It doesn't seem to be first person at all, and some kinda pirate-themed strategy game.
I have no affiliation to this game. I wanted to alert Rare of this trashy'ness.
I can't work out how to view the ad for it though since the Google Play Store page doesn't have a video on it.