Roboquest

The maximum Armor bonus is 60% and I was able to get this pretty consistently with Engineer. Here's what worked for me:

• There's a level up perk called "Chromatic Suit" where you select an element, and then after gathering 10 scrap you get 28% Armor and explode that elements damage on getting hit, I always chose the Pyro Suit option. There is then a sub-perk of this type called "Hardened Steel" which ups it to 36%
• The second main level up perk is called "Scrap Snacks", using Deploy increases drones fire rate by 70%, but importantly for us there is a sub-perk for this called "Unity" which increases your Armor and Movement speed by 12% while Scrap Snacks is active.

These 4 level up options give us 48%.

You then simply need to find 1 item which gives 12%, such as the corrupted items Avocado or Shell found in the purple areas.

I found this route with the level ups to be a lot more consistent than having to find multiple Armor items that I was trying on some of the other classes and only reaching 56% or something close. Don't forget you can also reroll level up perks twice to search for these more, I'd personally wait until you're at least half way in the run and have some of the others already.

There may be better routes for it, but thought I'd at least share how I popped it in the mean time so you can be on the look out for these level up perks while doing farming runs.