because you’re not supposed to be this cheesy “i’m safe at max distance” caster with pets
storm totems can attack enemies at the same range of devils max leash range - if you could place totems further they could attack further and extend the cheese of using them/long range pet caster
you have a fat 0 heals, your problem isn’t low armour from caster armour, your problem is you have no way of sustaining yourself when you take dmg; and you will take dmg, there is no way of avoiding that in grim dawn
phys res is also low, way too low for most builds’ comfort
pierce res and acid res isn’t capped (on GT avg rolls at least, might differ in game for you) and also no vitality overcaps
you are taking some skills that don’t really benefit you much, atleast according to your method of play (savagery is a melee hit) - while not taking really important skills like 1pt Mirror of Ereoctes
not taking Mirror or 1pt Nullification or overspending on Iskandra’s Elemental Exchange isn’t really your biggest problem, it’s the heal and resist
if you look at most caster builds they go either regen (way more than the puny 200 you have there) or they go lifesteal procs ex bat, combined with heal procs like dryad or behemoth etc or from items
health potion is not enough to sustain you and is not intended to be your main or sole method of heal, so you need something “moar”
upping your phys res to 20 or more will also help a fair bit (along with sorting your other resist overcaps ofc) - but you need a way to heal, be it lifesteal regen or heal procs or a combination of them
it’s not an issue of endgame items (these just make resist and dmg better boosted), it’s some key fundamental shortcomings in the build approach
i’ve tried pseudo pets with minimal heals myself (still way more than you had) and since the pets dont’ tank for you like true pets does, ie you still take aggro and all the dmg, it’s impossible to survive without heals, no matter how high you get your devil or totem dmg
examples of GTs you can look at (from the starter build compendium); particularly look at the approaches they go to in terms of healing, despite mad focusing in lightning “pets”
Vindicator, Level 100 (GD 1.1.9.1) - Grim Dawn Build Calculator (from Nery’s beginner vindicator)
Elementalist, Level 100 (GD 1.1.9.0) - Grim Dawn Build Calculator (from stupid_dragon’s beginner elementalist)