@mapes911, Below is my command that work on my machine. Feel free to try it out.
BUILD_PYTORCH_MOBILE=1 ENABLE_BITCODE=1 IOS_PLATFORM=WATCHOS IOS_ARCH=arm64_32 ./scripts/build_ios.sh

As for the bitcode, you can use the commands below to verify
#check the architecure
> lipo -i libcpuinfo.a
#Non-fat file: libcpuinfo.a is architecture: arm64_32

#verify bitcode
> otool -l libtorch_cpu.a | grep bitcode
# sectname __bitcode

Again, I haven’t run any tests on watchOS platforms. So I’m not sure whether they’ll work or not. But I’m curious to see your results. Please let me know if you have any questions. THanks.