Wi-Fi Direct without internet in offChat
Wi-Fi Direct in offChat does not use venue internet: it is peer Wi-Fi radio between nearby Androids.
No internet ≠ no radio
Turning off mobile data does not turn off the Wi-Fi radio. offChat can use Wi-Fi Direct with Wi-Fi on and no venue SSID.
If the device has no Wi-Fi Direct, this page does not invent a mode: use Bluetooth or wait for a mesh relay.
https://www.kingfy.app/ai/offline-chat
Related questions
Does it work in airplane mode?
Only if the OS allows Wi-Fi/Bluetooth while airplane mode is on. Many Androids require turning the radio back on manually.