48hrs later, 3rd day of trying -- all google result links are blue now && gsap forum threads.
I know the code by heart every line now (at least I feel like it).
I am missing something ridiculously obvious.
ScrollTrigger works without SmoothScroll, and vica versa.
Its either ScrollerProxy -- something that I am not doing right.
Or its the CSS of the containers.....
The worst bit, I've made this work before... 6months ago, using loco, and in production.
But now... I really don't know why....
By all accounts it SHOULD work!
Heres a quick codesandbox.