Website loading time issue

On a mobile device, my website takes too long to load. If you have any suggestions on how I might speed up website loading, I would appreciate it.

When we are diagnosed with google pagespeed insider , there suggest me to
Reduce JavaScript execution time.
url link :- https://domain_name/cdn-cgi/challenge-platform/h/b/scripts/alpha/invisible.js?ts=1680782400

You are hitting a challenge page with the page speed test, that’s not a JS file that’s loaded on the normal website, but only on the challenge page before loading your website.

That JS is supposed to be slow to validate the browser.