"you could write your crossplatform app logic in Zig, and only use Swift the UI" The UI glue code would be nothing special, and not improved by Swift vs Java.

"you could write your crossplatform app logic in Zig, and only use Swift the UI" The UI glue code would be nothing special, and not improved by Swift vs Java. The UI would be designed in a design tool. I like open source, so perhaps Penpot.