Default route

ip route del default
ip route add default dev wg0
ip route add 46.246.3.246/32 via 192.168.50.1 dev eth0


Namespace way

ip netns add physical
ip link set ens18 netns physical
ip -n physical link add wg0 type wireguard
ip -n physical link set wg0 netns 1
ip -n physical addr add 192.168.12.52/24 dev ens18
ip route add default dev wg0