Sometimes it doesn’t “click” until you experience it first hand.
You could start a post about it and see if there are any fabo members with examples of a speed increase with a converter swap.
I watched the video of the run....... you’re right, it does sound pretty flat in high gear........ so maybe there’s more speed in it with the current converter if you find a reason for it to be down on power.
Do you know what the rpm is at the finish line?