How to propage errors from nested Eithers in Arrow-kt?

Question

I have some code that looks like this:

data class MyStrings(val a: String, val b: String)

sealed class Error {
    object SpecificError0 : Error()
    object SpecificError1 : Error()
    object SpecificError2 : Error()
}

fun either2(): Either<Error, String> =
Either.catch { throw RuntimeException("Either 2") }.mapLeft { Error.SpecificError2 }

fun either4(): Either<Error, MyStrings> =
Either.catch {

    MyStrings(
        a = "Hello",
        b = either2().getOrElse { "" }
    )

}.mapLeft { Error.SpecificError2 }

This will swallow the error from either2().

I'm trying to find a way to throw this error from either2 back if possible.

I know I can do something like this:

fun either5(): Either<Error, MyStrings> =
either2()
    .flatMap {
        Either.Right(
            MyStrings(
                a = "Hello",
                b = it
            )
        )
    }

but it seems strange to call something before I need it!

Any thoughts on how I can change either4()? Sorry if this is a n00b question, but I'm still trying to wrap my head around functional programming and Arrow.

Thank you.