Hey Igor, I believe I encountered this in the past. https://lists.zx2c4.com/pipermail/wireguard/2021-September/007001.html
I'm not sure what your exact setup is since you mentioned it's a separate project presumably depending on WireGuardKit, but I can build libwg-go for arm64 just fine using the trick I mentioned in the linked thread. Just add this flag to Sources/WireGuardKitGo/Makefile. GOOS_iphonesimulator := ios Hope it helps.
