On the Thingy:91 X, Wi-Fi® scanning is used for location services. A full Wi-Fi scan across all bands can take 5-10 seconds, which consumes significant power. To reduce scan time and power consumption, the application restricts scanning to the 2.4 GHz band by default.
For detailed information on Wi-Fi scan timing, channels, and dwell times, see the Wi-Fi scan operation documentation.