I presume that what you use OpenVPN for, then, is just to gain access to your home LAN. If this is indeed the case, there are several options to override the usual
push "redirect-gateway def1"
setting in the server.conf. You find them described on this OpenVPN Wiki page, the simplest one of them all is to add these four lines to your client config file:
route 0.0.0.0 192.0.0.0 net_gateway route 64.0.0.0 192.0.0.0 net_gateway route 128.0.0.0 192.0.0.0 net_gateway route 192.0.0.0 192.0.0.0 net_gateway
The Wiki states explicitly:
Note that net_gateway is an internal variable to openvpn and does not need to be changed to anything
and, even more reassuringly, says that these four lines will work ...
If you do not know if your server uses def1 and do not want to check the logs to figure it out, just assume they DO use def1 and use the 4 routes. That will work no matter what.