Something triggering at precisely 3 PM every day is definitely scheduled rather than supernatural - your phone's just doing what something told it to do. The earlier answers nailed the main suspects: check your Settings for background app refresh, scheduled backups, cloud syncs, or calendar reminders. You might also have a recurring alarm you've forgotten about, or an app with its own daily task baked in (fitness trackers, weather apps, and messaging services love doing this).
Beyond those, dig into your battery usage history if your phone tracks it. Most Android and iOS devices will show you exactly which apps are consuming resources at specific times. If you see a major spike right at 3 PM, that's your culprit. Sometimes less obvious apps like email clients, location services, or even games with ads update on a daily schedule without you realizing it. I had something similar once where my phone would choke every afternoon, and it turned out to be a podcast app trying to auto-download new episodes at the same time my cloud backup was running - they were fighting for resources.
Try clearing your cache and restarting the phone once, then go through your individual app settings to disable any auto-refresh or notification features you don't actually need. If the freezing stops after that, you've found it. If it keeps happening, you can narrow it down by force-closing apps one at a time to see which one is the problem. It's tedious but usually works.