Pathfinder Poison Build
This is my current build plan so far as a Pathfinder build speced for poison. I am only missing a few keystones left and have a bit more damage and survivability left to get with pocket sand, kite runner, falcon technique, and leeching toxins.
https://maxroll.gg/poe2/passive-tree/w45y90qj
Gear wise get the highest physical damage bow you can as that calculates poison damage overtime. Extra elements do not help. Chaos damage is ok if you roll that. Getting +skill level gear is massive and makes damage output much better you can find it on quivers, bows, amulets, and rings. Broadhead quiver, Zealotbow/DoubleString Bow are best bases you can build your items around.
Skillswise the core is gas arrow. It applies your best poison and the cloud enables your damaging skills. I suggest armor break with armor break explosion as it works very well at clearing groups or stacking poison damage with commodity, bursting plague, deadly toxin, and swift affliction. Both sets are great.
Poison burst is fantastic single target for applying debuffs like maim and blind to bosses and elites or for armor breaking with corrosion.
Toxic Growth is your main clear and can be potent against large bosses. Get martial tempo the speed on this is terrible. Scatter shot gets you extra bombs same with the double string bow. Using area off effect support gems are also great from concentrated effect and magnified effect. Armour explosion is also great adding a second explosion. Best way to combo this with gas arrow is to shoot gas first then toxic growth. Activation is quicker that way.
Vine Arrow oh vine arrow, this puppy gets crazy good in the late game with support gems, poison, and especially gear that adds skill levels. It is terrible early and only good for cc. Mine is currently at 20 skill level with chaos gem, skill level from passive tree, gear and level 14 by default. This does crazy dps lasts a long time and out paces toxic growth in damage against stationary bosses or ones that do not move. Scattershot and Double string bow plant more each one increasing damage. Gas arrow powers up the vines. Put almost any support gem on this and it is great from slows for keeping them near vines longer or whatever else.