1. Can you confirm your current firmware version? Latest firmware is 126.96.36.199
You can check your firmware here:
Settings>System>About Phone>Software information
2. Your current router model name
3. Can your phone detect 6 ghz wifi in other area now?
4. If you put your phone and other devices in the same room of the router, can other device detect 6ghz wifi and your device still can't?
5. Please try reset Network: Settings>System>Reset options>Reset Wi-Fi, mobile & Bluetooth
6. Please try turn off the router and reconnect the signal.