Released protoc binary included in protoc-3.20.0-osx-aarch_64.zip was an x86_64 binary

[thii]

» curl -LO https://github.com/protocolbuffers/protobuf/releases/download/v3.20.0/protoc-3.20.0-osx-aarch_64.zip
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   667  100   667    0     0   2443      0 --:--:-- --:--:-- --:--:--  2434
100 2644k  100 2644k    0     0  3425k      0 --:--:-- --:--:-- --:--:-- 3425k

» unzip protoc-3.20.0-osx-aarch_64.zip
Archive:  protoc-3.20.0-osx-aarch_64.zip
   creating: include/
   creating: include/google/
   creating: include/google/protobuf/
   creating: include/google/protobuf/compiler/
  inflating: include/google/protobuf/compiler/plugin.proto
  inflating: include/google/protobuf/source_context.proto
  inflating: include/google/protobuf/wrappers.proto
  inflating: include/google/protobuf/type.proto
  inflating: include/google/protobuf/descriptor.proto
  inflating: include/google/protobuf/any.proto
  inflating: include/google/protobuf/field_mask.proto
  inflating: include/google/protobuf/duration.proto
  inflating: include/google/protobuf/api.proto
  inflating: include/google/protobuf/struct.proto
  inflating: include/google/protobuf/empty.proto
  inflating: include/google/protobuf/timestamp.proto
   creating: bin/
  inflating: bin/protoc
  inflating: readme.txt

» file bin/protoc
bin/protoc: Mach-O 64-bit executable x86_64

[fowles]

Dup of #9397 what we have now is a workaround for users with rosetta.

From the comments on that thread:

M1 binaries of protobuf are available via homebrew, it's also pretty straightforward to build it from source.