I've noticed, that the animator was pointing towards the Headpat layer instead of the heart-layer (for whatever reason), adjusted that one, yet it still does not trigger the layer whenever something as a declared sender, as hand, gets in contact with a receiver on hand-listener mode.
I literally tried the very same setup on a different avatar project, which had no VRCFury in it, and it works ... So yeah. I may be screwed, as my Project has multiple VRCFury dependencies (GoGo Loco, allocations, functions, toggles and so on).