What's the best way to to level up?

[Hatchback]

I'm only like 42 and the robots in the dlc are like level 60 on rank b. I'm playing as A2 and there are no side quests.

[Minneyar]

The easiest way requires you to beat the game first.

Pick one of the earlier chapters with 9S, when you can go to the Amusement Park but before everything there is hostile. Go to the entrance, kill all but one of the machines, hack that machine and control it, and then hack the gold robot statue in the fountain. Kill it to gain several levels at once.

[Oscar]

The area near the desert housing where you fought adam for the first time is pretty good for levelling.

[Xiango]

If you prefer leveling as A2 - go to the castle entrance in the forest zone, run through the castle killing everything until you get to the throne room save point, use it to transtport back to the entrance to respawn enemies and go again, takes about 2min per run.

[<blank>]

Me at Lvl 45-75, i went to the spawning pit in the housing complex (the place you first fight adam)

set auto heal, auto change equipment, auto attack and every auto chips you can get, enable it when you get there, and leave it there. I got to lvl 74 after i woke up.

From lvl 75 onwards, you can fight the bunny statue in the amusement entrance with ease. There i gained 3 levels per fight.... Then 2 then 1 until i got to lvl 99.

[Doomerang]

Make 2 50% exp chips. You can buy exp chips from the vendor at pascal's village chapter 7.1. put the game on easy and equip auto attack chips. go to the desert ruins where you first fought Adam and kill the never ending robots. You should get a level every 1-2 minutes, 70 plus you get them 2-5 minutes. You will get 99 fairly fast this way, maybe little over an hour. Make sure you have the 2 50% chips for 100% exp bonus

[Nazamura]

https://www.youtube.com/watch?v=_AnMx5iwFqc