Also, the recently published tensorflow-metal plugin for GPU support in Tf-macOS will only work in macOS 12.0+ so please don't try that on Big Sur at it won't work/will be unstable.

No, DO NOT use the instructions for installing tensorflow. Those are meant for macOS 12.0+ only. If you need instructions to follow installation instructions, check out https://www.tensorflow.org/install/pip#macos