-XX:-UseSHA doesn't disable UseSHA3Intrinsics.

Logs from running JDK 27 builds:

In mac-aarch64
java -XX:-UseSHA -XX:+PrintFlagsFinal -version | grep SHA
     bool UseSHA = false {product} {command line}
     bool UseSHA1Intrinsics = false {diagnostic} {default}
     bool UseSHA256Intrinsics = false {diagnostic} {default}
     bool UseSHA3Intrinsics = false {diagnostic} {default}
     bool UseSHA512Intrinsics = false {diagnostic} {default}
     bool UseSIMDForSHA3Intrinsic = true {ARCH product} {default}

In linux-x64
java -XX:-UseSHA -XX:+PrintFlagsFinal -version | grep SHA
     bool UseSHA = false {product} {command line}
     bool UseSHA1Intrinsics = false {diagnostic} {default}
     bool UseSHA256Intrinsics = false {diagnostic} {default}
     bool UseSHA3Intrinsics = true {diagnostic} {default}
     bool UseSHA512Intrinsics = false {diagnostic} {default}