I finally sped up my Pacegraph by simultaneously making the api calls for each running activity using cURL. Here’s the example I followed: https://www.phpied.com/simultaneuos-http-requests-in-php-with-curl/
Here’s the pace graph link again: https://pacegraph.eugenialeong.com/. It actually loads.
I also played around with the color interpolation in the graph, since my older runs aren’t in this dataset anymore (when I ran slower), and the splits in the current data varies less (meaning less color range).