How do I sync time on an old unconnected phone?

I have an old Samsung Galaxy S9 (Android 10) without a SIM. It is connected to WiFi. I use it to cast TV programs to the TV only. However, the time it displays is way off. I searched in Settings for Clock and timezone, without luck. The system clock on the phone is set to NZ, even though I am in Australia now. **Is there a way to set the clock manually?**