Your best bet for this right now would be kotlin multiplatform, which can target IOS native, browsers, and of course android. It also has an experimental wasm compiler but it's not ready for production usage. But you could actually target wasm with it.
Embedding WASM on IOS might be problematic because of Apple's rules regarding what is and isn't acceptable there. They've never liked people embedding interpreters in their apps. That's how they blocked flash as well. And that's how they continue to block the firefox and chrome browser engines.
Embedding WASM on IOS might be problematic because of Apple's rules regarding what is and isn't acceptable there. They've never liked people embedding interpreters in their apps. That's how they blocked flash as well. And that's how they continue to block the firefox and chrome browser engines.