THX. Still, unfortunately, I did not get it working (my bad maybe) in any way, even including other sources and videos so far. I would like to get some "road warrior" use case done, accessing my home network through an OpenVPN AS server residing at a VPS at Google Cloud, through which I would like to gain access to a client at home (Windows10), acting as gateway into the home network (settings done as showed in the video).
OpenVPN AS does work, client at home does get connection to OpenVPN AS (and gets an IP address from there), still I have acces to the internet as usual (which is intended). So far, so good.
BUT: With my laptop (Mac Book, OS X), as soon as I do establish the connection to OpenVPN AS (which works as well), all internet connection is lost and I cannot even ping the other client with the VPN internal network address - so lost all connections more or less.
Did also try try to use a Debian10 machine as client / gateway in my network, to rule our any windows issues, applying all kind of iptable setttings recommended etc., no success so far.
I am no Linux expert, neither a network engineer, so more than happy if anyone could enlighten me with a step-by-step guid how to do this.