I have a few devices like laptop , mobile , pc and I have wireguard installed in all of them with different config that they connect to same wireguard server . but I want to config a single wireguard on my router ( RB2011 Ui AS - 2Hnd-IN ) so all my device can connect to router and without running or installing wireguard send their data through wireguard vpn installed on my router . and if possible some site goes through wireguad and some of them not

Draw a network diagram of desired network
Make a plan, and detail the user requirements clearly
a. identify user/server or groups of users, including admin
b. identify what traffic flow they need.

You will need
one wireguard interface on router with an IP address.
All clients get assigned a wireguard IP within the subnet

You will need appropriate firewall rules on input chain and forward chain
You may need IP routes but only if another router is in the mix........

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