(Cc'ing Cameron in case someone at Apple can help) & @osy86 @rth7680 @agraf @akihiko.odaki
My understanding is binaries need to be signed to enable TSO (like Rosetta 2), but as an open source project we can not sign the qemu-system-x86_64 binary, thus QEMU can't use TSO.
IIUC we did the best we could, see for example https://gitlab.com/qemu-project/qemu/-/commit/664a79735e4.