Crashes after hitting 'Play'

I have just purchased and installed Minecraft Java Edition for MacOS.

Whenever I press 'Play' the green bar gets about 40% of the way across and then it quits.

I get the message "Java quit unexpectedly. Click reopen to open the application again." But clicking "Reopen" just brings me back o the start and it happens all over again. Every time.

And then I get the message on the Launcher window: "Error. Game crashed. An unexpected issue occurred and the game has crashed. We're sorry for the inconvenience. Close."