Can you force 2.4 GHz Wi-Fi?
A simpler method is to move far enough away from your router (make sure to unplug the nearest mesh node); this might force your phone to connect to the 2.4-GHz band. Since this band has a better range, your smartphone will eventually switch from 5 GHz with enough distance.
How do I access my 2.4 GHz instead of 5GHz?
To solve your problem you would have to temporarily disable the 5GHz Wifi of your router. If that is not possible you can try to force your phone to use 2.4 GHz. Some Android versions have a WiFi Frequency Band setting (see Wifi -> three vertical dots -> advanced).
Can I force Android 2.4 GHz?
How do I enable separate SSIDs for 2.4GHz and 5GHz?
How do I move a device from 5GHz to 2.4 GHz?
Do I need a separate SSID for 2.4 and 5GHz?