Beside the rules 5e actually there could be 4 player characters enough.
But ... let decide the players, I would like it with optional 6. Even without extra modding there were already old screenshots of a very old stage of baldurs gate 3 showing 5 player portraits. Hah!
And it would be more roleplay, more fun and more player friendly if the single- and multiplayer groups could decide for their own. And not tell the 5th or 6th friend to go!
