It's annoying and easy to forget, but you have to enable the high-quality line break algorithm per Text component in Compose. Or you have to set two flags (maxLines=1 and overflow=TextOverflow.Ellipsis). I usually end up with a TitleText and BodyText component in my codebases that set these flags internally so I don't have to remember.
I wasn't sure if this was a joke about Android being unintuitive so I was sad to see that enabling high quality line breaks is indeed something you have to configure:
https://developer.android.com/develop/ui/compose/text/style-...