If I understand your intentions correctly with this health buff, then you should quite simply be able to use the defaults in the primalitemconsumable to add your initial health value, and then spawn a buff at the same time which uses its defaults to add in the secondary set of health changes over time.
I haven’t opened the DevKit in a few days as I’ve been spending most of my time developing and extending my modelling and texturing skills in 3DSMax as opposed to my go-to of Maya, but from my recollection it should be possible to do what you’re wanting entirely in the existing ARK confines without needing a single implementation of graph-based logic.
-WM