In case anyone is interested I have updated by blog post on using a Pi as a VPN server so the instructions are compatible with Raspbian Buster.
https://blog.clanlaw.org.uk/pi-vpn-server.html
Cool. Also, don't forget that many of the better routers will act as VPN terminators.
Good point, I have added a note to that effect.
Good article. Have same problems but I use another vpn.
Very useful.