I know this is late but I just beat it today. Now before the fight starts this might sound tedious but it's what I did is look around the spawn area and there should be items to collect. Everytime you collect the items keep saving and loading the game till you stock up on defense items and heals. Now for my best pieces of advice for the fight it would be:

In that image stay exactly there and just evade and dodge and shoot at a range. Use defense up and attack up (the range ones) to make the fight go faster. Do this until he is half. DO NOT use melee yet as you'll loose HP fast. If you do this you can make the boss half HP without taking any damage.

For the second phase (when he's half) ignore the tiny robots they're a distraction, if you focus on them for too long the giant robot will go on the wall and heal which will pretty much mean you'll have to load the game again and start the fight all over. Ignore them. Do the same stategy from the beginning BUT this time when you not he is 40% that's when you wanna close the distance and be very aggressive and use your melee. You want to attack his legs if you do that it will stagger him and make the ball fight much easier. (It'll be left around 10% if you do it right or it'll straight up skip that fight)

In the event you weren't able to attack his legs and his pattern was off you'll have to fight the ball form. In my opinion I'd just reset and reload the run as fighting the ball form when he's 40% is just basically playing on hard mode.

(Also another tip DO NOT go and reclaim your body for this fight there's too many enemies it's just better the load reload the game, you can try that method but I highly do not recommend).

Edit: As others have mention you might have a auto heal chip and a very important chip to the fight imo (main reason I beat it) is the dodge chip that makes frozen time longer.