Safari bugging with interactions load on slower internet connection

I’m performing a final test of my site before publishing by throttling connection to 5Mbps, testing in in Chrome, Firefox and Safari on Mac OS.

Safari seem to be totally glitching on that speed with the interaction (boy on a raft on the very first page). Lottie button interaction also stutters. As soon as I turn off the speed throttle, everything is fine.
Mac OS Mojave 10.14.6, Safari 13.1.1
Here is my public share link: LINK

Here is a video showing the bug
https://www.loom.com/share/4af3d1be7d784ddabddd80d12b3ca0c2