I think perplexity has an app that installs via snapd and may have systemd timers but if you did not install anything then only the browser should be making cal

I think perplexity has an app that installs via snapd and may have systemd timers but if you did not install anything then only the browser should be making calls and only when you opened it so I guess just poke around in /etc/systemd, /usr/lib/systemd and /etc/cron* to see if anything was recently added without your knowledge. Also check your browser addons. Good luck!