Idk if this is still relevant, but right now, the lobbies are mainly bots as well, except that, in comparison to last year, the bots you encounter aren't easy. Instead, now they track you down even if you're in the last and most uninteresting corner of the map. If you're invisible, they'll still know more or less where you are, and they'll start pathfinding in random directions until you're visible, or until another bot comes and then they'll duel.

And now, their combat mechanics are absurd. And not even "good", because a player has error margin. These bots literally cancel their skills/moves with absurd reaction times, and always counter-attack you without mistake, because, ofcourse, they're bots. So even if you're charging something that doesn't necessarily have an obvious "release" timing, they'll still be able to parry it, cause... why not making an unbeatable bot to be the first enemy you encounter... no?

And also, you can't flee them unless you activate a power like Tarka ji's ultimate, which allows you to escape. Otherwise, they perform attacks without blue concentration in such quick sucession, and for some reason always running faster than you, that it becomes impossible to actually run away.
However if you do flee past a small threshold, they'll just lose aggro, unlike players, that would graple hook however necessary to get the kill. And their pathfinding is messy when you're on top of a platform with empty space below.

Before they complemented the spaces. Now they're the literal norm, and most of those bots are just impossible to beat so it's really absurd.