OpenWrt Complicated Setup

Dear members

i have a scenario that i hope a can set it up in my house

scenario 1 :

two openwrt router with version 21 and a 4G Modem

Router number 1 is connected to a 4G Modem with cable
i want to connect the router number 2 to the router 1 using wifi and share internet from router 1
i want to setup the same wifi SSID v 2.4 & 5ghz so the client can switch from router 1 to router 2 without disconnection seamless transition
i want to setup different wireguard connection to external provider (VPN) (i know how to configure wireguard) in both routers and keep the wifi connection between router 1 and 2

scenario 2 :

to extend more the wifi coverage

two openwrt router with version 21 and a 4G Modem

Router number 1 is connected to a 4G Modem with wifi 2.4ghz
i want to connect the router number 2 to the router 1 using wifi and share internet from router 1
i want to setup the same wifi SSID v 2.4 & 5ghz so the client can switch from router 1 to router 2 and the 4g modem without disconnection seamless transition
i want to setup different wireguard connection to external provider (VPN) (i know how to configure wireguard) in both routers and keep the wifi connection between router 1 and 2

scenario 3 :

1 openwrt router with version 21 and a 4G Modem

i want to connect the router to the modem using wifi and share internet from the 4g modem
i want to setup the same wifi SSID v 2.4 & 5ghz so the client can switch from router 1 to the 4g modem without disconnection seamless transition
i want to setup wireguard VPN connection to external provider (VPN) (i know how to configure wireguard) without loosing the wifi bridge between the modem and the router

please some help

best regards

The first scenario is the best if you use "Client (WDS)" on the second router.
The second scenario ... dismiss it.
The third scenario is the most common.
In any case, I would use 2.4 to repeat the signal, it has lower bandwidth but has higher penetrability.
As for the VPN, I suppose you will need "relayd" on the second router if you want to access any device connected to the second router.

hi @Willy thanks for your response , can you please show me how to do?

All is in documentation...