Netflix does let you add “guest” users in different households now, although It could be it just hasn’t hit you yet. When they announced the password crackdown it stopped Netflix working in my second household, but we just logged out and in and we haven’t been “blocked” since.
It seems for the initial debacle they blocked loads of accounts but I don’t know how often they do a ban wave or if they just figured the original announcement would get more people to buy subscription’s (which seems to have worked).
I spent hours trying to set up the GUI and couldn’t get it to work. Tried the AUR, Flatpack etc and no luck. In the end I just set up the command line version of open VPN with an Alias.