if you're still interested it should be quite easy to do if you use the bg3 toolkit. for context, in the stat editor: healing done in passive doesn't trigger (chaos sword) but healing done in boost does trigger (derivation cloak).
the sword of chaos is under MAG_BG_Sarevok_OfChaos_Greatsword in gustav dev in stat factor in the sword of chaos passiv (colomn x) use ApplyStatus(MAG_REGAIN_HP_4, 100, 0) instead of regain hp
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for context, in the stat editor: healing done in passive doesn't trigger (chaos sword) but healing done in boost does trigger (derivation cloak).
the sword of chaos is under MAG_BG_Sarevok_OfChaos_Greatsword in gustav dev
in stat factor in the sword of chaos passiv (colomn x) use ApplyStatus(MAG_REGAIN_HP_4, 100, 0) instead of regain hp
worst case scenario i could make it for you