I suppose I could write an

ApplyT

func that converts it to a string from a string pointer

Just following up, but that’s what I went with:

// UnwrapString converts a StringPtrOutput to a StringOutput.
//
// If the string is `nil`, an empty string will be returned.
func UnwrapString(sp pulumi.StringPtrOutput) pulumi.StringOutput {
	return sp.ApplyT(func(v *string) string {
		if v == nil {
			return ""
		}
		return *v
	}).(pulumi.StringOutput)
}

pulumi.Sprintf("serviceAccount:%s.svc.id.goog[%v/%v]", config.Require(ctx, "gcp:project"), UnwrapString(namespace.Metadata.Name()), UnwrapString(ksa.Metadata.Name()))

TIL you can just call

.Elem()

!