There seem to be a bunch of factors that can affect the outcome - so may not work for you if other issues are at stake!
In my case I have no DNS settings in the LAN Tab / I have Quad9 DNS settings in the WAN Tab plus the DoT settings to Quad9 - but that is all fall back only since I am running unbound locally on my AX86U. I do have DNS filter set to Router - with no alternate DNS records available in that section.
With the above in mind ... my OPVN3 settings look like this : - [click on it for larger display]
View attachment 35239
NOTE: I am using this for ONE particular device [AppleTV] because I have a presence in the UK - London [with TV license] but don't live there permanently. My Apple ID remains domiciled in the UK where it was/is region bound from the outset.
If you have devices on the Guest WiFi and those devices have their own DNS settings which may override those of the VPN - or devices which are prebuilt with locked down DNS - you will likely not succeed if those DNS servers are not in the correct region. Some devices may "leak" their location and that too may well block region bound streaming services. Also - if those guest wifi devices have browser caches filled with info showing locations other than the target region - the streaming may also fail.
I primarily use VPN services for security and privacy ... and get really annoyed by being blocked in my own region simply because some streaming service has decided that all VPN connections are dubious region breakers
!