Off topic, but in a TUN connection the client will be given a different subnet, often 10.8.0.0/something, with routing added.
Also, you will avoid problems if you change the server network from the common 192.168.1.0/24. Even if the client isn’t on that network, it is not unheard of for the modems, routers, etc. along the way to have that as well, and then confusion results.