Seeking Expert Level Help with Off-META Build

Hey all,

Doing a silly little build and just got to maps, where I'm not doing as well as I'd like.

Basic idea is to channel a skill, cast while channel: desecrate then volatile dead. Its fun to me to follow my giant SRS dudes around and watch them explode things. Does OK with bosses and OK with groups.

My goal is to be able to casually do yellow maps - no shaper or big endgame bosses.

This is the PoB of my current build:


Was thinking about a tree like this at lvl 90:


If you could basically help suggest better equipment, a better tree, and maybe better supports and supplementary skills.

Thanks - I know I'm probably asking for a lot.

EDIT: im pretty sure my profile is public - character name = evilolive

I'll probably hit reddit up for advice - its where the devs go and where the players can get help.