Thank you for the very informative answer. More than I could have hoped for.
Removing the delay and setting the position and opacity after the ScrollTrigger setup did the trick.
I did not fully understand the "ScrollTrigger startup phase" and when that happens. I will dig deeper into this.
I also read about "ScrollTrigger.config", which is a really good performance trick to know about (in certain scenarios).
Finally, I am experiencing some anomalies with how ScrollTrigger sequences (staggers) element-animations, and yes, the delay was to remedy that.
No doubt this has to do with the CSS I am using, but that is for another topic.
Thank you so much.