There's a lot of research on possibilities here! eHMIs (external human-machine interfaces) are the term.

https://www.theturnsignalblog.com/blog/ehmi/

https://www.mdpi.com/1424-8220/21/9/2912

It's unclear that there's a consensus on something that reliably works across cultural contexts, though - which, to be fair, is also a problem with human-human interactions!

A visual indicator the car sees a pedestrian would be helpful.

Such a good point. With human drivers I get very nervous of I cross in front them and haven't made eye contact with them. We need that for cars