You can create an expect class called PlatformSSLHandShakeException (or whatever) with no implementation, then in your iOS and Android source sets, you use an actual typealias to get the platform specific exception from Ktor.
E.g:
commonMain:
expect class PlatformSSLHandShakeException
androidMain:
actual typealias PlatformSSLHandShakeException = javax.net.ssl.SSLHandShakeException
iosMain:
actual typealias PlatformSSLHandShakeException = io.ktor.client.engine.darwin.WhateverTheEquivalentIsOnIos