I have a remote OpenVPN server setup and working.
From any device if I connect to that, and do what is my ip in google, it shows wan public ip address of OpenVPN server.
I would like to understand, if I could make openwrt act as OpenVPN client and connect to my OpenVPN server, so all my clients connected to openwrt will get public ip as remote OpenVPN server’s.
Keep in mind that OpenVPN is very cpu heavy and may be slow on your router (depending on the hardware you have). Wireguard, if it is an option four your situation, will be much more performant.
My need is to assume a different public ip, so that certain services can work correctly. Instead of making all clients connect to OpenVPN server, I thought it’s easier to make openwrt do it.
Can wireguard hide my actual public ip and assume remote ip?
If the router establishes the tunnel, and then it sends all the traffic through that tunnel, the apparent ip for all the devices connected to the openwrt router will be the public ip at the remote end of the tunnel. Just the same as you do now for individual devices.
And yes, wireguard will do exactly the same thing, only faster.