In the intro to Not only Swift #44, I briefly talked about a recent episode of Swift over Coffee, in which Mikaela and Paul talk about the question "should you use Swift everywhere, or is it better to learn other languages, too".
I encourage you to listen to their podcast, as they read the answers they've gotten from around the community and then provide their own thoughts.
It seems the idea of writing your code once, and then being able to deploy it "everywhere" sounds pretty promising to people, and there is no shortage of cross-platform tools that make this possible to a varying degree of quality.
The latest addition is Skip by Abe White - a transpiler that translates your Swift and SwiftUI code to Kotlin and Jetpack Compose. The intro video looks promising, and I can see how using a tool like this might be interesting to get you off the ground quickly if you need to create an app that works on both iOS and Android, and you neither have a an Android team, nor are you willing to use a tool like Flutter.
Here is a thread (including some source code) that shows how Amit built an app using Skip.
Definitely worth observing!