you can input architecture which is supported by your self hosted runner as an input to actions/setup-python@v3

steps:
- uses: actions/checkout@v4
- uses: actions/setup-python@v5
  with:
    python-version: '3.xx'
    architecture: <arm64|x86>

refer - https://github.com/actions/setup-python?tab=readme-ov-file#supported-architectures