It needs to be an IP address like what you show. It cannot be a domain name, so not sure what you mean by "always not resolve"
The interface address will have been given to you by the VPN provider. You must use the address they provide.
if you want to do custom DNS, that is fine, but that is handled in a different configuration option (not the WG config).
You may need to ask purevpn for support. Sometimes the best option is to get it working on a mobile phone or a computer... once you know that works, you can move that config to your OpenWrt system.
This will work, but only when the VPN is connected. If the VPN is not running, those servers will not be available, and your DNS resolution will fail. This will create a chicken-or-egg situation with the ability to actually start the tunnel since you can't resolve the domain.
It is possible that there is something special about the purevpn details that prevent it from working as expected with Wireguard. But this is why a computer or phone can be a good test -- you can prove that it is working first, then use those parameters to setup the WG connection on OpenWrt.
But given that you have another path...
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