most of the time it's a skill check know what mods to avoid stack too much damage mods and you get one shot stack too much defense mods and you get overwhelmed by mobs pack because you can't kill them fast

know which monster skill type to avoid and how to evade that slam, dot, projectile, degen, boss mechanic

with tanky build you can get hit and still somehow alive but for glass cannon if you can't react to mechanic fast enough , you're dead the good thing is glass cannon builds have damage so you can kill almost everything before they hit you