That's more of a job for an encapsulating protocol. (shadowsocks or similar) Wireguard isn't designed to be obfuscating alone. It's just a simple l3 udp tunnel with a minimal attack surface.
That's the traditional answer parroted in the Wireguard documentation but a few hours' serious thought and design is enough to reveal the fatal flaw: any encapsulating protocol will have to reinvent and duplicatively implement all of the routing logic. Perr-based routing is at least 50% of wireguard's value proposition. Having to reimplement it at the higher level defeats the purpose. No, obfuscation _has_ to be part of the same protocol as routing.
(Btw, same sort of thing occurs with zfs combining raid and filesystem to close the parity raid write hole. Often strictly layered systems with separation of concerns are less than the sum of their parts.)
In this case with the, I believe it’s called quantum tunneling by mullvad, it’s actually a good thing. Because the encapsulation protocol is just UDP/IP, a well established existing protocol that can masquerade as any kind of internet traffic easily.
amnezia-wg is quite cool and they have built the kmod too, I did some test so far they can works even in my location which block wireguard server quickly.
The mullvad apps do offer obfuscation options (shadowsocks, etc) but i agree it would be nice if something was baked into wireguard itself. I recently went through setting up shadowsocks over wg for my homelab and it was a good bit of effort
WireGuard is a protocol that, like all protocols, makes necessary trade-offs. This page summarizes known limitations due to these trade-offs.
Deep Packet Inspection
WireGuard does not focus on obfuscation. Obfuscation, rather, should happen at a layer above WireGuard, with WireGuard focused on providing solid crypto with a simple implementation. It is quite possible to plug in various forms of obfuscation, however.