I use OpenVPN from private server like you describe and so quirky, hit or miss, almost wonder if should subscribe to a commercial VPN. Primarily set up for remote viewing of security cameras as log into my home network, but VPN capabilities expand far beyond that. Loved it from overseas where thought I was in States and foreign blocks on programing suddenly wasn't as thought I was back in the States. My home computer is the server with the Asus router creating the OpenVPN and client protocol file. On the Mac, Tunnelblick client software. Simple setup, simply load the client file created by the router into Tunnelblick...done.
Worked fine initially, but after OS updates, Tunnelblick version updates, and Asus firmware updates has become a hit or miss. Now get an error message in Tunnelblick of obsolete protocol language which caused me to check for firmware update but that didn't resolve either. Resolved with some manual editing of client file (common problem from internet search) which worked until the next version update of Tunnelblick. GRRRRR! But the biggest problem is, some locations refuse to establish the tunnel. While Starbucks are OK, my work server as well as some public servers like the local library refuse the connection. Appears to be more than the IT department putting port blocks as I re-programmed my port designation to the secure 443 and still the problem. Probably the biggest frustration was when returned to daughter's in Switzerland (and due to physical distance couldn't troubleshoot to resolve, and what worked the prior year, suddenly only response that her IP provider, Swiss Telecom, connection status was good. Apparently we both used the same IP address (I never changed my system from default which is somewhat universal).
That is how you set it up to your private server, but having it work consistently is the issue.