Python's tiering has to do with testability and availability thereof, not modernness. In the case of 32-bit Windows, the reason it's still testable is because Windows still ships a 32-bit userspace, even if Windows itself only supports x86-64.

(From personal experience, testing Windows aarch64 is a massive PITA, even on GitHub Actions, which all common sense would indicate should have the best aarch64 Windows CI runner story.)