If children are going to play a video game they can do a lot worse than Sea of Thieves. It's designed to be a social game, even though you can play solo. This is actually punishing - you risk crashing your ship every time you check the crow's nest or go below-decks unless you drop anchor first and if others sight you, which they will, they'll always sink you because you are one against many and that just doesn't work.
I think the designer did this deliberately to ensure kids played as a team because there's much more they can get out of doing so. ie. it has to do with relationships, even if this is online. Best to play with friends, though.