Kotlin multiplatform should be a great tool pretty soon to share lots of code between iOS and Android withouth losing on app size. It is mostly business logic you will be able to share this way, but seeing how Compose and Swift UI look extremely similar, the cost of doing the UI twice won't be too bad.

This aside, I am surprised somebody changed framework not once but twice ! That must be a small codebase (or somebody that really loves to experiment).