It's difficult to know exactly what your issue is without having any URLs to check and see what is happening.
I understand that you might not want to block ads and lose revenue, but you need to understand that if you're allowing ads from all kinds of places, the ads could be running all sorts of code on your website without your permission. Online advertising gets a bad rep from things like this, and it takes the community to be diligent to ensure bad actors don't flood the internet with malicious ads. (These ads might not be intentionally malicious, but just poorly coded. Or simply too heavy to be run on your website.)
I've used GSAP in the creation of several thousand ads with varying degrees of complexity, it would have been rare that any of my builds had any effect on a website's performance, and if that did happen, the bugs were most likely code that I created as opposed to code created by @GreenSock