TextNow? Yes- i can text and phone over Wifi (but sadly can’t use a vpn to do so- TextNow won’t allow it- they used to- but not anymore i guess)
Yeah that is an issue for using it as a mobile modem. Unless it will let you tether, and you happen to have a WiFi connection. You will have to check the connections settings on the phone and see if the tether option works while plugged into your USB. Linux should auto see it and use it if the tether feature comes on for you.