Nothing stops you from using a self-signed certificate with a ridiculous expiration period for HTTPS between the reverse proxy and the device in question.
We used to use Firefox solely for internal problem devices with IP and subnet exclusions but even that is becoming difficult.
It's not different from IPSec, GRE, VXLAN, etc. It's just the new hotness.
We use VXLAN extensively in our network, btw, and IKEv2/IPSec tunnels between sites.
Just because it can be used to recreate VPNs traditionally used to remotely dial into a secure network zone doesn't mean it shouldn't be used in far smaller use-cases. WireGuard doesn't constitute anything like a full VPN solution on its own.