Advice for a support/summoner build

The goal is keep the build at lvl 150, clear every boss/dungeon with the theme of "having a spirit ash do the carrying" for every fight while I provide support healing

I will prioritize supporting my spirit ash over buffing my own DMG. I don't mind being squishy or vulnerable in some aspects to put extra emphasis on the importance of the spirit ash for my success 👍

Since I've never used spirit ashes, it seems like a unique way to play the game. Help please 🙏