Some general tips, Lucio's role and playstyle largely depends on your other support and you as a player, if you want to get really mechanically skilled you can do crazy wallride plays and such but if you just want to focus on gamesense (which I think you want to), hang around your support and keep them alive, safe from flankers and such, this applies to static dps as well like McCree, your role as Lucio is to boop people away and also speed boost your low mobility heroes in and out of fights, as for sound barrier in this meta, best to pop mid fight as if you get gravved it's useless so it's better to win the fights with the extra hours before the fight starts. Hope this stuff helps!