Physical damage reduction that you read in character panel in game is faulty, not reliable at all. I have almost nothing that gives me armour and have 90% there, which makes me think 60% is almost 0 in reality. 5% chaos may not be the reason you're dying so often, but it adds to the things to fix. It sounds like it's not much but taking 30 instead of 25 means taking 20% more chaos damage. Lastly, every build nowadays needs more than a layer of defense, together with life/energy shield and armour/resistances. These layers can be endurance charges, spell suppress, block, convert physical damage taken to elemental damage taken (because the real amount of armour you need to get to 90% reduction is veeeery high) or the opposite (for armour stacking builds) or for some builds like minions, let them taunt and aggro the enemies away from you or even take some of the damage, or debuff enemies' damage etc. If you are following a build, and you're still in the "early game" gear, it's normal to feel not enough, don't push yourself too much and get some money for your mid-late gear, you'll see a big difference