In a bit of an interesting/weird move, Ubisoft has announced that the upcoming Anno 1800 will be another one of their games, following Division 2, that will only be able to be purchased on Uplay and the Epic Game Store but only after launch. Prior to launch (April 18) the game can be pre-ordered on Steam and anyone who buys it there will get the game through Steam. Ubisoft will provide patches and future game content to the Steam version at the same time as everyone else. Since you need Uplay for the game anyway Steam users will still be able to play multiplayer with anyone that buys it on the other stores.
https://www.anno-union.com/en/ubisoft-is-partnering-with-epic-games-store-for-anno-1800/
https://www.anno-union.com/en/ubisoft-is-partnering-with-epic-games-store-for-anno-1800/