Can't you also get FIPS 140-3 WireGuard by compiling wireguard-go with the new native FIPS support in Go?
The ciphers used by WireGuard are not FIPS 140-3 certified. So you have to also change the ciphers, as is done in this project.
alt Hacker News
The ciphers used by WireGuard are not FIPS 140-3 certified. So you have to also change the ciphers, as is done in this project.