Can anyone recommend the best way to do low latency audio on windows and osx?
If you're programming in Rust, you can use the cpal crate, which wraps all these. I'm not sure cpal has astonishingly good performance in all cases, but I plan to work with the authors. It doesn't have an Android back-end yet, but such a thing should be possible.
If you use JUCE (https://juce.com/) you'll get a single API for all the different audio APIs on macOS, Windows, iOS, Android, Linux, etc.