I just leveled a pyro myself actually. Those one shots you receive from time to time sure are fun lol.
My advice is to not waste your chest and shoulder component slots on ugdenbog leathers. Throw those leathers on your boots, and gloves (maybe even your pants) and then you have your chest and shouders free for some armor absorption components. Even something like scaled hide on your pants could go a long way. You dont wanna go into act 2 of ultimate with uncapped pierce res AND low armor with low armor absorption. Youre asking for the one shots.
I’d also suggest more points in blood of dreeg. If not for the heal, then for the OA steroid.
Upgrade your relic if you can. If you want to farm blueprints, then first farm up some skeleton keys, and go to the merchant in the ancient grove. Every session he changes his blueprint stock, and the boss there is easily beatable with a ranged toon, which will inch you closer to a legendary set you can use.
I’d also take those 3 spare points from owl, take the 1 from spider, remove imp (since the damage isnt that high and you have confusion on your flashbangs) and go for chariot of the dead. Theres a heal there, more OA, so you can crit more, and the stun res that you want. Getting chariot allows you to remove the red crossroads point. You should have 3 points left over, which i would suggest go into behemoth for its proc, which you should attach to your blast shield. Then you get massive health regen whenever your blast shield procs.
The only resistance reduction that stacks with itself is if it says “-X% resistance” if its worded in any other way, the game only prioritizes the highest value. But all different types of phrasings combine. So say it says “-x% resistance” on two skills, and on another it says “X reduced targets resistances”. Those will all stack. But if you have “x reduced targets resistances” on two skills, and “-x% resistance” on another, then only the highest value of the prior will combine with -x% resistance.
Oh yeah and unless you really value that vitality resistane on second rite, maxing it out does nothing for you. You arent vitality focused and chaos is only a secondary damage type