Hey, glad you got it working. I’m late to the party, but I got a similar solution here: https://github.com/stratself/tswg. Basically just mounts your own wg.conf to the container and get Tailscale connected over it

Since Wireguard is peer-to-peer, I suppose the “intended” way is to install Tailscale on every client. But it is possible to use the router as a VPN gateway as per this [OpenWRT guide])https://openwrt.org/docs/guide-user/services/vpn/tailscale/start#force_lan_traffic_to_route_through_exit_node). Hope you get it working anyhow