google cloud platform – How can I monitor application performance?

I’ve encountered an issue where I’m not sure which direction to take. My application is using GCP. I want to monitor the performance, mostly in requests, not infrastructure, as far as i’ve looked I can monitor backend performance with google cloud trace(correct me if i’m wrong).

For the frontend it’s a bit tricky, I’m not really sure how I can measure the duration a page takes to fully load and send the value somewhere I can exploit it. The idea is to save all the metrics and print them in dashboards and trigger alerting etc.. (preferably on gcp but not closed to other tools).

Any idea/track would be appreciated, thanks !