Tethering is normally used to pass through WiFi to ethernet or vice-versa. IIRC if you tether WiFi to an ethernet connection that’s got 192.168.0.x, the DHCP in connman will use subnet 192.168.1.x, otherwise it uses 192.168.0.x. It sounds like you have no ethernet in the motorhome so 192.168.0.x it is. If you do connect to ethernet at home I would expect connman to switch to serving 192.168.1.x and your phone should just get a new IP on that subnet.
Have you tried that?