Your demo seems to be totally non-functional (errors are being thrown that are unrelated to GSAP, so nothing is even showing). That makes it almost impossible to troubleshoot.
I'd recommend just stripping everything out including React if you can - just get the basic concepts going with some colored <div> elements and post back here with any GSAP-related questions. Just please keep in mind the forum guidelines - we're happy to answer GSAP-specific questions but we can't provide free general consulting about logic issues, 3rd party libraries, etc.
Marquee Endless Loop Not Working
in GSAP
Posted
The helper function loop link not working. How I could get that? https://greensock.com/docs/v3/HelperFunctions#loop