Hey, folks new to OpenWRT, recently installed it on my AX23 v1.2 router and connected it to the main (ISP)router using wireless via relayd as a range extender. I wanted to use VPN for all traffic on this router, searched through articles couldn't find how to implement this. As the router is in bridge mode the traffic don't goes through the VPN
Correct.
If you make a guest wifi on this router which is on its own subnet then traffic of that guest wifi will go through the router instead of just bypassing it, so will be routed via the VPN.
You don't need relayd. Set up a conventional routed client which does lan->wwan routing. Then you can use any of the various instructions to set up a whole house VPN client the same as if you had a wired WAN.
How can I do that, is there a guide for it ?
Thank you in advance
Yes, there is a guide. It assumes that you're starting from a default install, so please be sure to reset your device to defaults first.
https://openwrt.org/docs/guide-user/network/wifi/connect_client_wifi
Then you can install OpenVPN from there.
https://openwrt.org/docs/guide-user/services/vpn/openvpn/client-luci
Alternatively, if your VPN service has the option to use Wireguard, that is much more performant and easier to configure.
https://openwrt.org/docs/guide-user/services/vpn/wireguard/client
Let's take a look at your config in text form:
Please connect to your OpenWrt device using ssh and copy the output of the following commands and post it here using the "Preformatted text </> " button:
Remember to redact passwords, MAC addresses and any public IP addresses you may have:
ubus call system board
cat /etc/config/network
cat /etc/config/wireless
cat /etc/config/dhcp
cat /etc/config/firewall