u/DepressingAura

In the first zone, there are zip lines that lead you up to the high areas where melee enemies can not swarm you, and you can shoot down at the boss without much difficulty. It's a great spot for cover. It is also great for when the deadeye enemies spawn, and you can take them out from a safe(r) spot to drop their shards. When depositing shards, you can bait the boss to the edge of the arena by just standing behind cover, because he'll constantly be walking towards you. This leaves the middle open, and much less dangerous when depositing shards. However, being on ground level leaves you open to melee enemies, so make sure you have a weapon that is capable of dealing with multiple enemies at once while waiting for the boss to make his way to the edge of the arena. Reboot with Grenade Bulelts or Wardens with Explosive Rounds are great for this.

The second zone can be very overwhelming. There's very little cover, and the robots with guns are extremely accurate. Ideally, at least one of the capture zones will be on the second level, where the railings can block a lot of incoming damage. Staying prone can make capturing zones trivial on the second level. On the ground level, utilize the small rooms where the ammo crate and self-revive spawn if things get too heated. There's plenty of time. No need to rush. When the core is exposed, you can stay under the circular catwalk, and you will not be able to be hit with projectiles or meatballs from the core.

The third zone is a lot larger than the first two. However, the boss moves around a lot. There are two high platforms towards the center of the arena. These two platforms are the best places to be. There will be targeted strikes which will chase you off those platforms, but using a grappling hook or kinetic jump can allow you to instantly get back up on one of the platforms. Because the boss is so large, it is very easy to take shots at the edge of the boss without him being able to shoot back. This boss is not about brute force. It is about timing your shots, and not overcommiting.

Going in with Shattered Shield or Echo Shell is highly recommended.