wg0 doesn't go down by itself. Packets are always delivered to wg interface as long as it is marked as 'UP' (or 'enabled', if 'UP' sounds to you like having an

wg0 doesn't go down by itself. Packets are always delivered to wg interface as long as it is marked as 'UP' (or 'enabled', if 'UP' sounds to you like having anything to do with some kind of "connection") when your routing table directs them there. When they hit the wg interface when the other endpoint is unreachable for whatever reason, they are either dropped, or queued, or get ICMP unreachable response generated for them, depending on situation. This is done internally by wireguard.